June 20, 2024

4:00PM

CFNS Seminar:  Gravitational form factors of light nuclei
Speaker:  Fangcheng He (Stony Brook University)
Location: Stony Brook University - Room C-120 

Abstract: I will present our recent studies of the gravitational form factors (GFFs) for deuteron and helium-4 using the impulse approximation including leading order exchange current corrections, which include the pair interaction, plus the seagull and the pion exchange interactions, modulo the recoil corrections. The deuteron GFFs are analysed using Reid soft core potential, and helium-4 GFFs are assessed using the K-Harmonic method with simple pair nucleon potential,  and Jastrow trial functions using the Argonne v₁₄ potential. We also estimate the cross section of threshold J/Psi photo-production off light nuclei using these GFFs. Recording

May 30, 2024

4:00PM

CFNS Seminar:  Identity of the Proton
Speaker: Wenliang Li (Stony Brook University)
Location: Stony Brook University 

Abstract:  Proton as a member of the baryon family, holds a baryon number (identity) of 1. Unlike the structureless leptons, the baryons are constructed of quarks and gluons. In this colloquium, we will dive into the mystery of who carries the identity (baryon number) for the proton: quarks? gluons? or both?

Recording

May 16, 2024

4:00PM

CFNS Seminar: A basis approach of hadronic systems on the light front
Speaker: Guangyao Chen (Jacksonville University)
Location: Stony Brook University

Abstract:  The study of hadrons from the perspective of the light front offers distinct benefits, particularly as the partonic degrees of freedom within Quantum Chromodynamics (QCD) become well-defined in the infinite momentum frame. Basis Light-Front Quantization (BLFQ), having matured over the last decade, becomes a powerful method for solving problems related to the strong force. The BLFQ framework employs an effective Hamiltonian that integrates the one-gluon-exchange QCD interaction with mechanisms for confinement across both transverse and longitudinal dimensions. This approach has facilitated in-depth studies of diverse hadronic systems, notably baryons and quarkonia. The light-front wavefunctions (LFWFs) derived from these studies are instrumental in assessing a broad spectrum of hadronic observables. Such observables encompass decay constants, light-cone distribution amplitudes, form factors, and transitions, both radiative and semi-leptonic. Furthermore, they extend to parton distributions and Generalized Parton Distributions (GPDs) for quarkonia, as well as the electromagnetic and axial form factors, transverse densities, Parton Distribution Functions (PDFs), GPDs, radii, and axial and tensor charges of baryons.This talk aims to provide a summary of the current state of the Basis Light-Front Quantization (BLFQ) approach and its application to research at the future Electron Ion Collider. A key focus will be on the process of diffractive vector meson production, which will be studied using the BLFQ light-front wavefunction.

Recording

May 2, 2024

4:00PM

CFNS Seminar: Twisted Gradient Flow renormalization scheme and the Λ Parameter
Speaker: Jorge Luis, BNL
Location: Stony Brook University, Room C120 Slides

Abstract: We review our study of a finite volume renormalization scheme that combines a gradient flow-based coupling, the use of twisted boundary conditions, and a special asymmetric geometry. We argue that this scheme has several advantages that make it particularly suitable for precision determinations of the strong coupling constant in QCD, including translational invariance, an analytic expansion in the coupling, and a reduced memory footprint. We test the scheme numerically by determining the Λ parameter of the pure SU(3) Yang-Mills theory. Like most gradient flow-based couplings, this determination suffers severely from the so-called topology freezing, which is overcome here by a judicious definition of the coupling: the determination is projected into the sector of zero topological charge. We show that this definition has no relevant impact on the determination of the Λ parameter.

Recording

April 18, 2024

4:00PM

CFNS Seminar: Precision QCD Program at Belle II
Speaker: Anselm Vossen (Duke)
Location: Stony Brook University, Room C120 Slides

Abstract: Due to the excellent control over the initial state, electron-positron annihilations provide for the cleanest way to probe QCD in hadronization.T he Belle II experiment is a next generation B factory, taking data around the (4S) resonance. It is located at the SuperKEKB accelerator which achieved a world record luminosity. Between 2019 and 2022, Belle II accumulated more than 400 fb-1 of data, about half of the Belle dataset. Since the beginning of 2024 Belle II has started taking data again after improvements to accelerator and experiment. With its state-of-the-art PID, the Belle II is an ideal place to study hadronization at medium energies. I will present an overview of the Belle II experiment as well as current activities in the study of precision QCD at Belle II with a special focus on the extraction of fragmentation functions. 

Recording

April 4, 2024

4:00PM

CFNS Seminar: Signatures of baryon junctions in semi-inclusive deep inelastic scattering
Speaker: David Frenklakh (SBU)
Location: Stony Brook University, Room C120

Abstract: Since a baryon is a composite particle, one may wonder which degrees of freedom are carrying the conserved charges, including the baryon number. A baryon junction, that arises naturally in a gauge-invariant baryon wavefunction, is a good candidate to associate the baryon number with. In this talk I will go over the possibilities to test the flow of baryon number experimentally, focusing on the recent proposal of using semi-inclusive deep inelastic scattering. The rapidity distribution of produced baryons predicted in a model with baryon junctions depends crucially on the Regge intercept of exotic states with hidden baryon number. Such intercepts can be estimated with the help of Feynman-Wilson analog gas model and I will discuss recent developments in this approach. Finally, I will explore the possibility of identifying such exotic states with particular glueballs that were reported in lattice QCD.

Recording

March 20, 2024

4:00PM

CFNS Seminar: NNLO QED for l-p scattering with McMule
Speaker:  Yannick Ulrich (University of Bern)
Location: Stony Brook University, Room C120 Recording 

Abstract: Precise lepton-proton scattering experiments need similarly precise theory predictions. It is now possible to model electron-proton and muon-proton scattering at next-to-next-to-leading order (NNLO) in QED. These corrections can be similar in size or even larger than the two-photon exchange contribution that is often a goal of the measurement and hence need to be brought under control. In this talk I will introduce the McMule framework for NNLO QED calculations and explain the theory background that is required to use it. I will then present results for the MUSE experiment.

March 7,2024

4:00PM

CFNS Seminar: Photonuclear probes of high-density nuclear matter
Speaker: Jackson Pybus (MIT)
Location: Stony Brook University, Room C120 Recording

Abstract: Understanding the properties of high-density nuclear matter is a longstanding challenge. Short-Range Correlations (SRC) are pairs of strongly interacting nucleons which comprise the highest-density states of matter found on Earth. These SRC pairs influence the overall structure of nuclei and are also linked to the partonic structure of bound nucleons. While our knowledge of SRCs and their impact on small- and large-scale QCD has come primary from electron-scattering data, gaining a complete understanding of SRCs requires a variety of complementary measurements.T  he SRC-CT experiment, conducted in Hall D at the Thomas Jefferson National Accelerator Facility, employed a real photon beam to perform a high-energy measurement of nuclear targets, using meson photoproduction as a novel probe of SRCs in light nuclei. This measurement has allowed us to perform the first observation of SRCs in photoproduction reactions, allowing for an improved understanding of the nuclear ground-state. We have also used this data to perform the first measurement of near- and sub-threshold photoproduction of J/ψ off bound protons, offering the first insights into the gluon content of nuclei and large-x. In this talk, I will present the first results from this experiment and describe future measurements aiming to advance our understanding of SRCs and their partonic structure.

February 29, 2024

4:00PM

CFNS Seminar: Nuclear Suppression of Light Charmonia Measured at SeaQuest
Speaker: Noah Wuerfel (BNL)
Location: Stony Brook University, Room C120 Recording

Abstract:The E906/SeaQuest experiment at Fermi National Accelerator Laboratory took scattering data with the 120 GeV Main Injector Proton beam on liquid hydrogen and deuterium targets, along with carbon, iron, and tungsten targets. Within the data are a significant number of muons coming from the decay of J/Ψ and Ψ' particles. In this talk, I present a study of the suppression of these light, charmed particles by cold nuclear media at SeaQuest. The data are divided into two analyses: first, the cross sections for charmonia production on the carbon, iron, and tungsten targets is compared with the cross section on the hydrogen and deuterium targets to study the cross section ratio as a function of the atomic mass of the target; and second, each of the carbon, iron, and tungsten targets’ effects on charmonia production are studied as a function of the transverse momentum and Feynman-x kinematic dimensions in the ranges 0.0 ≤ pT < 1.5 GeV and 0.4 ≤ xF < 0.95. Finally, the unbinned results are compared with previous results from the E772 experiment and the binned results are compared to theoretical predictions from the Color Evaporation Model.

February 19, 2024

2:00PM

CFNS Seminar: Toward a microscopic picture of QCD dynamics
Speaker: Felix Ringer
Location: Stony Brook University, Room C120

Abstract: Abstract: High-energy particle colliders play a critical role in unraveling the fundamental interactions between elementary particles, which has led to the formulation of the Standard Model of particle physics. The strong force in nature, described by the theory of quantum chromodynamics (QCD), governs the interaction of quarks and gluons, which constitute the main building blocks of the visible universe. Despite significant theoretical and experimental progress since the development of QCD spanning over more than five decades, many fundamental questions remain: How do the dynamics of quarks and gluons give rise to emergent structures such as nucleons and nuclei? What is the phase diagram of nuclear matter and what are the real-time and non-equilibrium dynamics at collider experiments and in the early universe? Addressing these questions requires the development of new paradigms in nuclear theory, closely aligned with experimental efforts such as those at the Electron-Ion Collider, the main future nuclear physics facility in the US where the structure of nucleons and nuclei will be explored in great detail. In this talk, I will discuss recent progress toward answering some of these challenging questions using perturbative QCD, AI/machine learning, and quantum computing, and outline the road ahead.

Recording

February 18, 2024

4:00PM

CFNS Seminar: Nuclear Tomography with e-A scattering at JLab
Speaker: Miguel Arratia Munoz (UC Riverside)
Location: Stony Brook University, Room C120 Recording

Abstract: I will describe recent measurements of hadron production in electron-nucleus scattering experiments at JLab using the CLAS detector. These studies aim to map the 3D structure of nucleons bound in heavy nuclei and to constrain the mechanism of hadronization within nuclei. Additionally, I will discuss planned experiments involving polarized 11 GeV electron beams, high rate and a range of nuclei from carbon to lead.

February 16, 2024

3:00PM

CFNS Seminar: Probing quark matter and hadronization using energy flow substructure.
Speaker: Yang-Ting Chien
Location: Stony Brook University, Room C120

Abstract: Understanding nuclear structure and hadronization from quantum chromodynamics (QCD) has been an outstanding challenge since its discovery 50 years ago. With the future Electron Ion Collider (EIC) and high-resolution detectors being planned at Brookhaven National Laboratory (BNL), it is a great opportunity to advance our knowledge of quark and gluon dynamics in the nonperturbative regime. In this talk, I will explain how streams of energy flows -- jets and target fragments -- coming out from high energy collisions may shed light on how quarks and gluons evolve into and distribute inside hadrons and nuclei, through the imprints in energy flow substructure. In particular, we show that leading two-particle charge correlation is sensitive to hadronization mechanisms which motivates further theory and phenomenological studies. Current-target correlation in deep inelastic scattering of nuclei also significantly enhances the sensitivities to quark and gluon distributions. Capabilities of particle identification and forward particle detectors at EIC will hopefully enable us to probe unprecedentedly these phase spaces which may lead to discoveries.

Recording

February 14, 2024

2:00PM

CFNS Seminar: Hadron as a many-body parton system: from parton interactions to non-perturbative phenomena
Speaker: Andrey Tarasov
Location: Stony Brook University, Room C120

Abstract: Due to the phenomenon of confinement, the hadron cannot be understood as a compound state of independent quarks and gluons but rather represents a strongly bounded many-body parton system. The dynamics of this system gives rise to such fundamental properties of the hadron as spin and mass. How the spin and mass of the hadron arise from the parton dynamics is an outstanding question of modern nuclear science. The parton dynamics can be probed in high-energy scattering experiments using the factorization approach. However, there is a wide class of observables that cannot be described within the conventional factorization schemes due to various reasons, including non-perturbative phenomena. In my talk, I will give several concrete examples and propose a solution based on applying the background field techniques, which provide a unified treatment of parton interactions. I will argue that the application of such techniques allows us to obtain a complete picture of the multi-parton dynamics in QCD and shed light on the origin of the proton spin and mass.

Recordings

February 12, 2024

2:00PM

CFNS Seminar: Harnessing Intricacies of Jets for Breakthroughs in QCD

Speaker: Kyle Lee

Location: Stony Brook University, Room C120 zoom

Abstract:Jets have been pivotal in the advancement of Quantum Chromodynamics (QCD) since its inception, serving as a bridge between collider phenomenology and the formal language of field theory. Modern jet analysis empowers us to achieve significant breakthroughs in our understanding of QCD and enables direct comparisons with experimental data. In this talk, I will outline several key research areas within jet physics that I am spearheading. These include deepening our understanding of heavy quark dynamics, investigating the effects of the medium, unraveling the hadronization process, and probing spin physics. I will highlight the application of these studies at current colliders like the LHC and RHIC, and look ahead to precision measurements at the future Electron-Ion Collider (EIC) to discuss how perturbative techniques serve to enhance our understanding of the intriguing non-perturbative aspects of QCD.

Recording 

February 9, 2024

3:00PM

CFNS Seminar: (New) physics from lower dimensions
Speaker: Adrien Florio (BNL)
Location: Stony Brook University, Room C120

Abstract: Recent years have witnessed impressive progress in the direct numerical study of quantum many-body systems in real-time, from first principles. I will present my perspective on how these methods, combined with insights from quantum information science and the promise of quantum advantage offer exciting opportunities to learn more about relativistic quantum field theories and how they pave the road to better understanding relevant phenomenology of real-world, 3+1 dimensional theories such as QCD. I will exemplify this view by presenting my recent work (arXiv:2312.05298) on the repartition of distillable entanglement in the ground state of the Schwinger model and how it relates to the confining behavior of the theory. I will also discuss our recent study (arXiv:2310.18312) of "QZD", our new toy model of nuclear matter.

Recording

February 8, 2024

4:00PM

CFNS Seminar: Intelligent Experiments Through Real-time AI: Fast Data Processing and Autonomous Detector Control for sPHENIX and Future EIC Detectors
Speaker: Dantong Yu (New Jersey Institute of Technology)
Location: Stony Brook University, Room C120 Recording

Abstract: With an ever-increasing demand for high-precision data for discovery science and precision measurements, all major high-energy nuclear and particle experiments face the challenge of dealing with the large volume of raw data generated from sophisticated, high-rate detectors.  Data collection must be balanced with available hardware and cost limits on DAQ (Data AcQuisition system) bandwidth and offline computing resources to capture, store and process signal events. Two prototypical examples are the upcoming sPHENIX experiment, the DOE next-generation heavy-ion physics experiment at the Relativistic Heavy Ion Collider, and the future EIC experiments planned to be online circa 2030 at BNL.  To meet this challenge, we propose developing a selective streaming readout and control system comprising state-of-the-art AI-based fast data processing and autonomous detector control systems to effectively sample the total collision rate delivered by the accelerators while maintaining final data throughput for offline storage at a manageable level within available DAQ bandwidth and storage and computing capacity.
Our real-time AI-based algorithms operate on high-rate data streams, allowing the identification of important rare-physics events from abundant background collisions in the sPHENIX's p+p runs, as well as in the future EIC experiment. We aim to ensure adaptability, high speed, and real-time requirements in our proposed online AI algorithms. In particular, we will integrate two complementary coprocessors, Nvidia GPU (training) and FPGA (inference), and use open-source industry tools and our community-developed \hlsfml to translate high-level machine learning and neural networks models into GPU kernels and FPGA bitstreams. Our proposed solutions minimize the complexity of hardware implementations and maximally sample the delivered high luminosity collisions for discovery science. Demonstrating such a complete system integration will be a first step in autonomous control loops of powerful online AI algorithms for large-scale, complex nuclear physics experiments.

February 7, 2024

2:00PM

CFNS Seminar: A comprehensive insight into nucleons at the Electron-Ion Collider
Speaker: Shohini  Bhattacharya (BNL)
Location: Stony Brook University, Room C120

Abstract: Quantum Chromodynamics (QCD) is the theory governing the strong interactions that bind quarks and gluons, collectively known as partons, to form nucleons - the fundamental building blocks of visible matter. Achieving a profound understanding of the partonic structure of nucleons stands as a crucial milestone, and the forthcoming Electron-Ion Collider (EIC) at the Brookhaven National Laboratory is poised to be the ultimate tool in nuclear physics for this purpose. In this talk, I will explore a few of my research endeavors, aiming to address key questions such as, "How can we measure the orbital motion of partons within nucleons?" and "How can we uncover quantum anomalies in the distributions of partons within nucleons, and what can we learn from them?" The state-of-the-art theory discussed in this talk plays a pivotal role in providing comprehensive insight into nucleons, exploring the origins of spin, mass, and symmetry breakings - all of which form the bedrock of QCD and the EIC.

February 5, 2024

2:00PM

CFNS Seminar: Exploring the Intersections between Nuclear Physics and Quantum Information Science
Speaker: Niklas Mueller, University of Washington
Location: Stony Brook University, Room C120

Abstract: I will discuss the role played by Quantum Information Science and Technology (QIST) in addressing grand-challenge nuclear physics problems and beyond, focusing on real-time dynamics (like thermalization and scattering) and elusive quantum and thermal phases. My presentation will draw connections to current experimental priorities, such as the Electron-Ion Collider, which pose significant challenges from the theoretical perspective because of their computational difficulty. My talk will focus on how quantum simulation can provide insights into these exciting questions, and I will highlight the opportunities for scientific exploration enabled by the ability to quantum simulate one quantum system with another. Emphasizing the significance of the so called “entanglement frontier”, I will present several examples where QIST can contribute to advancing our understanding of subatomic physics, even before quantum technology reaches the level of maturity required for precise simulation. Additionally, I'll discuss interdisciplinary work at the intersections of lattice gauge theory, topological phases, and fault-tolerant quantum computing, illustrating the symbiotic relationship between physics exploration and QIST development.

February 1, 2024

4:00 PM

CFNS Seminar: Thermal Pure Quantum States for Quantum Simulations of Abelian and Non-Abelian Lattice Gauge Theories at Finite Temperature 
Speaker: Connor Powers (University of Maryland)
Location: Stony Brook University, Room C120 Recording 

Abstract: Our understanding of the QCD phase diagram is hindered by the sign problem encountered by standard lattice gauge theory techniques. Quantum computers offer a potential route around this sign problem, but the simulation of systems at finite temperatures poses a challenge on quantum computers. Here, I will discuss a recently-introduced technique for estimating thermal expectation values in lattice gauge theories on quantum computers, which we call physical thermal pure quantum (PTPQ) states. An extension of thermal pure quantum (TPQ) states, originally introduced in a classical computing context, PTPQ states are suited to the simulation of lattice gauge theories while retaining key properties of TPQ states. Quantum circuit implementations will be discussed, followed by numerical demonstrations of simulating Abelian and non-Abelian lattice gauge theories with PTPQ states at finite temperature and chemical potential. 

January 18, 2024

4:00PM

CFNS Seminar: Seeing quarks and gluons
Speaker: Prof. George Sterman  (Stony Brook)
Location: Stony Brook University, Room C-120 Recording

Abstract: I'll review some of the history that led to the methods of perturbative QCD, recall how I got involved with those advances, and comment on how they may develop in the coming decades.

January 17, 2024

2:00 PM

CFNS Seminar: Light-Ion Physics with EIC
Speaker: Christian Weiss (Jefferson Lab)
Location: Stony Brook University, Room C120 Slides

Abstract:  I will discuss the physics applications of eA(light) scattering at EIC and the connection between high-energy-scattering and low-energy nuclear strucure

December 14, 2023

4:00PM

CFNS Seminar: Photon radiation by rotating fermions in magnetic field
Speaker: Matteo Buzzegoli (Department of Physics and Astronomy, Iowa State University)
Location: Stony Brook University, Room C-120 Recording

Abstract:  In heavy ion collisions there is a big difference between the measured nonprompt direct photon yields at low transverse momentum and the model predictions. I will show how the electromagnetic radiation emitted by a quark in the presence of a magnetic field can be enhanced in a rotating medium. Preliminary results suggest that, due to the large magnetic field and angular velocity of the quark gluon plasma, the inclusion of this synchrotron radiation assisted by rotation is likely to solve the discrepancy in the previous models. I will discuss the role of boundary conditions in fast rotation and how the same formalism can be used to assess finite volume corrections on the chiral magnetic effect.

December 7, 2023

4:00PM

CFNS Seminar: Hot and Dense QCD Shear Viscosity

Speaker: Isabella Danhoni (Institut für Kernphysik, Technische
Universität Darmstadt)

Location: Stony Brook University, Room C-120 and Recording

Abstract: Transport coefficients, such as viscosity, can be calculated theoretically in weakly coupled quantum field theory, and present interesting information about hydrodynamic models of heavy-ion collisions. We present results for shear viscosity calculations at almost leading order in weakly coupled QCD in a regime of high baryon density, where the chemical potentials are greater than the temperature. In previous work, we have shown that shear viscosity at leading log order in this regime is dominated by quark scattering."

December 6, 2023

10:30AM

CFNS Seminar: The MUSE Experiment

Speaker:Wan Lin (Rutgers, The State University of New Jersey)

Location: Stony Brook University, Room C-120 and zoom

Abstract: The MUon proton Scattering Experiment (MUSE) at the PiM1 beam line of the Paul Scherrer Institute is simultaneously measuring the elastic scattering of electrons and muons from a liquid hydrogen target to extract the charge radius of the proton. Both beam polarities will be measured over the course of the experiment. By comparing the four scattering cross sections, the experiment will provide unique muon proton scattering data with a precision sufficient to address the proton radius puzzle and test lepton universality. This talk will give an overview of the proton radius puzzle, past and current efforts on the search for violation in lepton universality, and present blinded preliminary data on the measured cross sections. 

November 30, 2023

4:00PM

CFNS Seminar: Insights into the cold QCD medium 

Speaker: Charles-Joseph Naim (Stony Brook University)

Location: Stony Brook University, Room C-120 and Recording

Abstract: Understanding the effects of cold nuclear matter (CNM) is still a puzzle, especially in terms of their magnitude. These effects vary depending on the hard process, impacting the rapidity and transverse momentum distributions of the dilepton. Deciphering CNM effects is crucial for comprehending suppressions observed in hA collisions from fixed targets to LHC energies, but also in heavy-ion collisions. To address this challenge, we propose a global study of Drell-Yan and quarkonium production in pA and \piA collisions. Our goal is to establish a complete,coherent, and universal formalism for characterizing the impact of CNM effects. Additionally, the upcoming Electron-Ion-Collider (EIC) will play a crucial role in providing strong additional constraints on these effects. We will explore the extent to which the EIC can enhance our understanding of these effects.

November 16, 2023

4:00PM

CFNS Seminar: Exclusive electroproduction of Phi off the proton and neutron with CLAS12 detector

Speaker: Niveditha Ram (CEA, Saclay)

Location: Stony Brook University, Room C-120 and Recording

Abstract: The Generalized Parton Distributions (GPDs) offer a comprehensive framework to study the longitudinal momentum distributions of partons, transverse position, orbital angular momentum, and the associated correlations. Experimental exploration of these GPDs involves the study of hard exclusive processes in electron-nucleon scattering, with a photon or meson in the final state. The CLAS12 collaboration at Jefferson Lab operates an all-purpose generic detector, successfully conducting an imaging program of nucleons to access GPDs related to various quarks. Under the kinematics of Jefferson Lab, the CLAS12 detector typically reaches the valence quarks of the nucleon. However, given that φ is an s ̄s meson and the sea strange quark distribution is considerably smaller than gluons in this kinematic regime, investigating the φ meson serves as a direct probe into gluon dynamics. The differential cross-section and Beam-Spin Asymmetry (BSA) as functions of t stand out as key observables for measuring the gluonic radius of the parton. This presentation will outline the progress of three analyses, with a shared objective of accessing the gluon GPDs of a nucleon through the study of the φ meson.

November 15, 2023

4:00PM

CFNS Seminar: High-precision Møller Polarimetry for MOLLER

Speaker: Dr. Eric King (Temple University)

Location: Stony Brook University, Room C-120 Recording

Abstract:  Møller polarimetry is an ideal method for interspersed electron beam polarization measurements—the large scattering cross section and large analyzing power of Møller scattering allows for periodic high statistical-precision measurements—providing key checks on continuous beam polarization measurements during experimental operation. The upcoming MOLLER experiment, scheduled to start in Jefferson Lab’s Hall A in 2025, aims to make the most high-precision measurement to date of the weak mixing angle and requires a ±0.4% accuracy for beam polarization, accounting for both systematic and statistical errors (the latter being negligible). Achieving accurate beam polarization measurements below a 0.5% threshold presents significant challenges due to inherent systematic errors associated with Møller polarimetry—the largest of which arise from the use of a polarized iron foil as our target. Valuable insights gained from recent experiments in Hall A have laid the groundwork for achieving the high-precision ±0.4% error goal for MOLLER. Discussion here will focus on the specific challenges encountered, key systematic efforts, and some recent Møller polarimeter systematics study data taken during SBS at JLab.

November 9, 2023

4:00PM

CFNS Seminar: Mesons, baryons and tetraquarks in small systems at LHCb

Speaker: Matt Durham (LANL)

Location: Stony Brook University, Room C-120 and Recording

Abstract:One of the defining features of Quantum Chromodynamics is confinement, which prevents isolated quarks and gluons from being observed.   Partons are bound within a rich spectrum of hadrons, which have various quark content, binding energy, and size.  With precision vertexing, full particle ID, and a fast DAQ, the LHCb detector is uniquely well suited for measurements of a wide range of conventional and exotic hadrons. I will present recent LHCb results on mesons, baryons, and tetraquarks that are sensitive to the mechanisms enforcing confinement. In particular, I will show how these mechanisms are affected by the hadronic environment, and discuss our understanding of hadronization in a hadronic medium in the lead up to the EIC.

November 2, 2023

4:00PM

CFNS Seminar: The Optimal use of Segmentation for Sampling Calorimeters

Speaker: Fernando Torales Acosta (LBL)

Location: Stony Brook University, Room C-120 and Recording

Abstract: One of the key design choices of any sampling calorimeter is how fine to make the longitudinal and transverse segmentation. To inform this choice, we study the impact of calorimeter segmentation on energy reconstruction. To ensure that the trends are due entirely to hardware and not to a sub-optimal use of segmentation, we deploy deep neural networks to perform the reconstruction. These networks make use of all available information by representing the calorimeter as a point cloud. To demonstrate our approach, we simulate a detector similar to the forward calorimeter system
intended for use in the ePIC detector, which will operate at the upcoming Electron Ion Collider. We find that for the energy estimation of isolated charged pion showers, relatively fine longitudinal segmentation is key to achieving an energy resolution that is better than 10% across the full phase space. These results provide a valuable benchmark for ongoing EIC detector optimizations and may also inform future studies involving high-granularity calorimeters in other experiments at various facilities

October 26, 2023

4:00PM

CFNS Seminar: Precise jet substructure studies at RHIC and LHC

Speaker: Oleh Fedkevych (Georgia State University / CFNS)

Location: Stony Brook University, Room C-120 and Recording

Abstract: Jets are collimated sprays of particles abundantly produced in collider experiments. The variety of jet-production processes allows for the use of jets to test fundamental properties of the Standard Model of particle physics, as well as to perform searches for new particles predicted by its extensions. Consequently, within the last decade, jet substructure physics has received a lot of attention and has found many crucial applications. In particular, jet substructure was used to fit the strong coupling constant, to constrain PDFs, and to test high-precision perturbative QCD calculations. Furthermore, jet substructure is sensitive to interactions between partons produced via hard scattering processes with the dense medium formed in proton-nucleus (pA) or nucleus-nucleus (AA) collisions, which makes it an important tool for the search for QGP signatures. 

In this talk, I will discuss several jet substructure observables, including jet angularities and the primary Lund Plane, and their relevance for the LHC and RHIC phenomenology. In particular, I will present NLO+NLL' accuracy level resummed predictions for a set of jet angularities and discuss the procedure for extracting non-perturbative contributions based on the transfer matrices approach

Recording

October 5, 2023

4:00PM

CFNS Seminar: Local equilibrium and Lambda polarization in high energy heavy-ion collisions

Speaker: Andrea Palermo (Stony Brook University)

Location:Stony Brook University, Room C-120 and zoom

Abstract: Local equilibrium and Lambda polarization in high energy heavy-ioncollisions
Abstract : The polarization of the $\Lambda$ hyperon has become an important probe of the Quark-Gluon Plasma produced in heavy-ion collisions. Recently, it has been found that polarization receives a substantial contribution from a term proportional to the symmetric derivative of the four-temperature, the thermal shear tensor. We review the theoretical derivation of this result using the local equilibrium density operator, and discuss numerical computations for Au-Au collisions at 200 GeV. It is shown that, provided that the hadronization hypersurface is isothermal, the thermal shear can restore the agreement between the experimental measurements and the predictions of the hydrodynamic model, solving the long-standing "polarization sign-puzzle"

Recording

CFNS Seminar:  New developments in the exclusive diffraction 
event generator 
Sartre
Speaker:  Tobias Toll (IIT Delhi)
Location: Stony Brook University, Room C-120 and zoom
Abstract: I will talk about the latest developments in Sartre, which is an event generator for exclusive diffraction at small x, ep, eA and UPC. I will discuss the inclusion of subnucleon structure in the nuclear geometry, how we may extend the generator to also include pion (and kaon) structure in leading neutron events, and into inclusive diffraction. I also discuss how we use machine learning techniques to make the generator more flexible.

Slides
Recording

CFNS Seminar:  Strong Interactions and Bound Nucleon Structure: From CLAS12 and GlueX to ePIC
Speaker:Prof. Or Hen (MIT)
Location:Stony Brook University, Room C-120 and zoom
Abstract: Since the discovery of quarks nuclear physicists have been trying to understand the relation between the lower-resolution description of nuclei using protons and neutrons and their underlying higher-resolution description in terms of quarks and gluons. At the intersection of these two paradigms are Short-Range Correlations (SRC): pairs of strongly interacting nucleons whose distance is comparable to their radii. Due to their overlapping quark distributions and strong interaction SRC pairs reach local densities comparable to those existing in the outer core of neutron stars and serve as a bridge between low-energy nuclear structure high-density nuclear matter and high-energy quark distributions.
In this talk I will present results from high-energy electron scattering, hadron knockout, and photo production experiments that probe the structure and properties of SRCs across scales: from their effect on the behavior of protons in neutron-rich nuclear systems through their role in our understanding of strong interactions at short distances and the impact of nuclear interactions on internal quark-gluon sub-structure of nuclei. Looking to the future I will also discuss next generation studies at the forthcoming Electron-Ion Collider under construction at Brookhaven National Lab.

Recording

CFNS Seminar:  Search for baryon junctions in photonuclear processes and heavy-ion collisions at STAR
Speaker: Nicole Lewis, (BNL)
Location: Stony Brook University, Room C-120 and zoom
Abstract: Baryon number is a strictly conserved quantity in QCD and is conventionally assumed to be divided equally among the three valence quarks in baryonic matter.  An alternative model is the baryon junction: a Y-shaped configuration of nonperturbative gluons that is connected to all three valence quarks and carries the baryon number.  In this talk we will present two new measurements from the STAR experiment which can help distinguish between these two pictures.  Baryon number is closely associated with baryon stopping, a well-documented phenomenon in heavy ion physics where an excess of baryons compared to antibaryons is measured even at mid-rapidity.  Because the valence quarks carry the baryon’s electric charge, if they also carry the baryon number we would expect baryon number transport and charge transport to be the same over large momentum transfer.  These quantities are measured to high precision by comparing identified particle spectra from Ru+Ru and Zr+Zr  isobar collisions and results show that at mid-rapidity baryon stopping is a factor of two larger than charge stopping in central collisions.  Photonuclear collisions are a type of ultraperipheral heavy-ion collision where one nucleus emits a quasi-real photon which interacts with the other colliding nucleus.  Further supporting the argument for the existence of the baryon junction, significant baryon stopping and rapidity asymmetry are observed at low transverse momentum in semi-inclusive photonuclear processes in Au+Au collisions.  These measurements will inform future measurements of identified particles at RHIC, the LHC, and the upcoming electron-ion collider.

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CFNS Seminar: News on proton structure and alpha_s extraction from HERA and CMS and prospects from EIC
Speaker: Katarzyna Wichmann, (DESY)
Location: Stony Brook University, Room C-120 and zoom
Abstract: HERA inclusive Deep Inelastic Scattering (DIS) cross sections are a backbone of every parton density (PDF) extraction. Additional information about gluon density and the strong coupling alpha_s can be obtained from a variety of jet data. Both PDFs and the estimation of the strong coupling value and uncertainties are crucial for every experiment including a proton in the initial state and for the precision measurement both in SM and BSM physics. I will present the recent results on the NNLO PDFs and alpha_s extraction coming from HERA and CMS jet cross sections and show some studies how EIC DIS data can influence the precision of the proton densities.
Transverse Momentum Dependant parton distributions (TMDs) can give access to information on “3-dimensional imaging” of hadrons. I will introduce a phenomenological work on the first extraction of global TMDs from inclusive DIS, Drell-Yan and fixed target data using a parton branching method and discuss how the new CMS multi-jet cross sections can give us some insight about the TMD effects included in the Monte Carlo simulations.

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CFNS Seminar:  3D Imaging and jet transport coefficients of cold nuclear matter 
Speaker: Zhongbo Kong, (UCLA)
Location: Stony Brook University, Room C-120 and zoom
Abstract: We provide two complementary viewpoints for quantifying the modification of parton dynamics within cold nuclear matter compared to free nucleons. Firstly, from a transverse-momentum-dependent (TMD) factorization standpoint, these modifications can be captured through nuclear-modified TMD parton distribution functions (nTMD PDFs) and TMD fragmentation functions (nTMD FFs). Secondly, through a collinear QCD factorization approach at high-twist, these modifications are expressed through multi-parton correlation functions, which encode the well-known jet transport coefficient (i.e. \hat{q}) for the nucleus. We conduct a global analysis of experimental data to quantify the universality and kinematics dependence of the nuclear medium property as reflected in both approaches. We also provide projections for the corresponding observables at the future electron-ion collider.

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CFNS Seminar: Charmonium as a probe of the initial and final state effects in heavy-ion collisions with ALICE at the LHC
Speaker: Minjung Kim, (UC Berkeley)
Location: Stony Brook University, Room C-120 and zoom

Abstract:Measurements of J/ψ production have been a valuable probe to study the properties of the hot and dense medium created in heavy-ion collisions, also known as the quark-gluon plasma (QGP). The suppression of J/ψ production in A-A collisions relative to p-A collisions was observed at the Super Proton Synchrotron (SPS) in the late 1990s, which was proposed as the smoking gun of the QGP as a consequence of colour screening in the QGP medium, which prevents charmed quark-antiquark pairs from binding to each other. 
The increase in the charm quark production cross section at the Large Hadron Collider (LHC) compared to previous collision programmes at SPS and RHIC has opened up new perspectives for the measurement of charmonium production. In central A-A collisions, the recombination of abundantly produced charm quarks seems to be an important mechanism for charmonium production. In addition, charmonium production could be measured in different collision systems with various observables,   having different sensitivities to initial and final state effects.
In ALICE (A Large Ion Collider Experiment), J/ψ production is measured both at mid- and forward rapidity down to zero transverse momentum in all collision systems via the dielectron decay channel and the dimuon decay channel, respectively. This talk will present a selection of recent charmonium measurements with ALICE at the LHC, focusing on their role as probes of initial and final state effects in heavy ion collisions.

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CFNS Seminar:  Light Front Hadronic Structure in the Instanton Vacuum  — Light Mesons
Speaker: Wei-Yang Liu, (CFNS, SBU)
Location: Stony Brook University, Room C-120 and zoom
Abstract: This work addresses quark models of hadronic structure on the light front, motivated by the QCD vacuum structure and lattice results. The spontaneous breaking of chiral symmetry on the light front, is shown to parallel that in the rest frame, where the non-local instanton induced ${}^{\prime }$'t Hooft interaction plays a central role. By rewriting this interaction solely in terms of the good component of the fermionic field, a scalar chiral condensate emerges in the mean-field approximation, which is identical to the one obtained in the rest frame. The pions and kaons emerge as deeply bound Goldstone modes in the chiral limit, with the scalar-isoscalar sigma meson mode as a threshold state with zero binding. We explicitly derive the light front distribution amplitudes (DAs) and partonic functions (PDFs) for these mesons. The DAs and PDFs are in good agreement with those extracted from the QCD instanton vacuum in the rest frame, using the large momentum effective theory (LaMET). The QCD evolved DAs and PDFs compare well with available measurements, as well as recent lattice results.

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CFNS Seminar: Studying Hadronization at LHCb
Speaker: Christine Aidala, (University of Michigan)
Location: Stony Brook University, Room C-120 and zoom
Abstract: A key question in quantum chromodynamics (QCD) is how to relate the quark and gluon degrees of freedom of QCD to the hadrons we can observe in nature.  A great deal of effort over more than half a century has been dedicated to understanding and describing hadron structure, in particular proton structure, in terms of partonic constituents.  Much less attention has been focused thus far on the inherently dynamical process of hadron formation from colored degrees of freedom.  The LHCb experiment at CERN, with its outstanding hadron identification capabilities, offers unprecedented opportunities to study hadronization in a high-energy hadronic collision environment.  Current results and future prospects will be discussed.

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CFNS Seminar: Real-time non-perturbative dynamics of jet production in Schwinger model: quantum entanglement and vacuum modification
Speaker:  Shuzhe Shi (Stony Brook University)
Location: Stony Brook University, Room C-120 and zoom
Abstract:  The production of jets should allow testing the real-time response of the QCD vacuum disturbed by the propagation of high-momentum color charges. Addressing this problem theoretically requires a real-time, non-perturbative method. It is well known that the Schwinger model [QED in $(1+1)$ dimensions] shares many common properties with QCD, including confinement, chiral symmetry breaking, and the existence of vacuum fermion condensate. As a step in developing such an approach, we report here on fully quantum simulations of a massive Schwinger model coupled to external sources representing quark and antiquark jets as produced in $e^+e^-$ annihilation. We study, for the first time, the modification of the vacuum chiral condensate by the propagating jets and the quantum entanglement between the fragmenting jets. Our results indicate strong entanglement between the fragmentation products of the two jets at rapidity separations $\Delta \eta \leq 2$, which can potentially exist also in QCD and can be studied in experiments.

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CFNS Seminar: Probing a new regime of ultra-dense gluonic matter using high-energy photons with the CMS Experiment
Speaker: Zaochen Ye (Rice University)
Location: Stony Brook University, Room C-120 and zoom
Abstract: Gluons are found to become increasingly dominant constituents of nuclear matter when being probed at higher energies or smaller Bjorken-x values. This has led to the question of the ultimate fate of nuclear gluonic structure and its interaction with external probes at extreme density regimes. In heavy-ion ultraperipheral collisions (UPCs), the coherent heavy-flavor vector meson via photon-nuclear interactions is of particular interest, as its cross section can directly probe the nuclear gluon density function. 
In this talk, we will present a new measurement of coherent J/Psi photoproduction with the forward neutron tagging technique in UPC PbPb collisions at 5.02 TeV. The production cross section will be presented, for the first time, as a function of the photon-Pb center-of-mass energy in UPCs up to about 400 GeV, corresponding to an extremely low x of ~ 5x10-5. We will discuss the physics implications of this new result, as well as exciting opportunities in future LHC heavy ion runs.

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CFNS Seminar: Rapidity space entanglement in gauge theories
Speaker: Yizhuang Liu  (University of Krakow)
Location: Stony Brook University, Room C-120 and zoom
Abstract:
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CFNS Seminar: Probing Nucleon Structure and Interactionsin Light Nuclei
Speaker: Prof. Nathaly Santiesteban (University of New Hampshire)
Location: Stony Brook University, Room C-120 and zoom
Abstract:  Quasi-elastic experiments allow us to extend our understanding of nucleons in the nucleus and reaction mechanisms. With a good understanding of these effects, light nuclei can be used as effective neutron targets. We will discuss the results of the analysis of the unpolarized 3H and 3He Quasi-elastic data taken by the E12-11-112 experiment at Hall A in 2018. The physics analysis of this set of data aims to extract the neutron magnetic form factor, GnM , using 3H/3He ratio in the Q2 range of 0.5-3 GeV2/c2. Next, an overview of the Dynamic Nuclear Polarized Target at the University of New Hampshire will be given, the development of which will provide access to the deuteron tensor asymmetry Azz in the quasi-elastic region which has never been measured before.
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CFNS Seminar: Searching for Wavelike Dark Matter with Dielectric and Superconducting Cavities
Speaker: Dr. Raphael Cervantes (Fermilab)
Location: Stony Brook University, Room C-120 and zoom
Abstract: Haloscopes consisting of microwave cavities connected to low-noise electronics have been deployed to search for bosonic dark matter candidates with masses of a few μeV. But the dark matter mass is unknown, so haloscopes must be tunable to search through the photon coupling vs. mass parameter space. Therefore, the scan rate for haloscope experiments is a crucial figure of merit and is proportional to the cavity’s quality factor and the square of the detection volume. State-of-the-art experiments like ADMX currently use half-wavelength copper cavities with 𝑄∼80000. But traditionally-employed half-wavelength cavity is that they suffer from a significant volume reduction at higher masses. The first part of the talk describes ADMX-Orpheus, which mitigates the volume-scaling issue by operating a tunable, dielectrically-loaded cavity at a higher-order mode. This allows the detection volume to remain large at higher frequencies. The ADMX-Orpheus inaugural run excludes dark photon dark matter with kinetic mixing angle χ > 10⁻¹³ between 65.5 μeV (15.8 GHz) and 69.3 μeV (16.8 GHz), marking the highest-frequency tunable microwave cavity dark matter search to date. The second part of the talk describes SERAPH, a new effort at Fermilab/SQMS to implement SRF cavities with superior quality factors in wavelike dark matter searches. I will discuss proof-of-principle measurements that demonstrate that ultra-high Q cavities have unprecedented sensitivity to dark photon dark matter. Next, I will discuss plans to commission a dark photon dark matter search over a wide frequency range. Finally, I will discuss the applications of ultra-high Q cavities for axion searches and progress toward realizing ultra-high Q cavities under multi-Tesla magnetic fields.
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