TBD

CFNS Seminar: TBD
 Speaker: TBD
Location: Stonybrook University - Room C-120Zoom
Abstract: TBD

March 5, 2025

4:00PM

CFNS Seminar: Critical Fluctuations at High Baryon Densities, and Lessons fromthe STAR Fixed-Target Critical-Point Search
Speaker: Zachary Sweger (UC Davis)
Location: Stonybrook University - Room C-120Zoom

Abstract: For over two decades, researchers at the Relativistic Heavy Ion Collider (RHIC) have mapped the phase diagram of QCD matter. Signatures of a quark-gluon plasma (QGP) phase created in high-energy Au+Au collisions have been observed, and the evolution of these QGP signatures tracked with varying collision energy. Yet one of the large unanswered questions of the RHIC experimental program is whether there is a critical point in the QCD phase diagram, as many models predict there should be. Recent fixed-target and collider data collected by the STAR experiment are being used to search for fluctuations in the number of protons observed in heavy-ion collisions, as such fluctuations are predicted in the vicinity of a critical point. The status of the critical-point search will be presented, along with a discussion of what was learned from STAR’s recent data.

February 27, 2025

4:00PM

CFNS Seminar:  PHENIX results in the context of the EIC Era
Speaker:  Lurii Mitrankov (Stonybrook University)
Location: Stonybrook University - Room C-120 Zoom
Abstract: Heavy ion physics stands at a critical juncture. In the U.S., the Relativistic Heavy Ion Collider (RHIC) program is set to conclude in 2025, making way for the next-generation Electron-Ion Collider (EIC). In Europe, the study of ultra-relativistic nuclear collisions will continue as part of the high-luminosity phase of the Large Hadron Collider (HL-LHC) following the upcoming Long Shutdown. As the field transitions into this new era, it is essential to engage in a broad community discussion on past achievements and the future direction of heavy ion physics in the context of the EIC. The PHENIX experiment ended data collection in 2016, nearly nine years ago. Since then, the PHENIX collaboration has gained significant expertise in analyzing long-accumulated data and has made substantial progress. In this talk, I will highlight recent PHENIX results and attempt to discuss the remaining open questions shaping the future of the field.

February 13, 2025

4:00PM

CFNS Seminar:Ready for it? Quantum Utility in High Energy Physics
Speaker: Henry Lamm (Fermilab)
Location: Stony Brook University - Room C-120 ZOOM
Abstract: While quantum computers have the potential for opening new avenues in theoretical high energy physics, the precise boundary where such a utility exists at present is murky. In this talk I will discuss recent works that have sought to formalize problems of interest into quantum algorithms, and determining their ultimate quantum resource costs.

January 30, 2025

4:00PM

CFNS Seminar: Factorization and Resummation Beyond Leading Power: The SCET Approach
Speaker: Robert Szafron (BNL)
Location: Stony Brook University - Room C-120  Zoom

Abstract:Factorization theorems play a crucial role in understanding and predicting the behavior of physical processes in Quantum Field Theory. By separating long- and short-distance physics, they allow for the resummation of large logarithms that often arise in perturbative calculations. This talk will provide a modern Effective Field Theory perspective on factorization. We will then delve into the complexities of next-to-leading power corrections, where the traditional understanding of factorization is challenged. Specific examples will be presented, including the amplitude for di-Higgs production in gluon fusion and the cross-section for Deep Inelastic Scattering near the threshold. These examples will highlight the current progress and ongoing challenges in understanding factorization and resummation beyond leading power. SLIDES

December 12, 2024

4:00PM

CFNS Seminar:  Three's a Crowd: Short-Range Correlations in the A=3 System
Speaker: Axel Schmidt (GWU)
Location: Stony Brook University - Room C-120
Slides

Abstract:  The formation of short-range correlations between nucleons appears to be a universal phenomenon in nuclei, appearing in systems as small as the deuteron and as large as lead. Though only a fraction of nucleons may participate in a correlation at any moment, correlations may play significant roles in determining the symmetry energy in the equation of state in dense nuclear matter, double beta decay matrix elements, and the EMC Effect. While experiments have revealed a lot about the properties of these correlations, it has been challenging to make contact with microscopic nuclear theory. The A=3 system, owing to its simplicity, presents an opportunity to compare to ab initio calculations and gain insight into how pairs form and behave. In my talk today, I will review an experimental campaign conducted at Jefferson Lab studying helium-3 and tritium and discuss what we have learned, and the new questions that have arisen. In particular I will discuss efforts to understand the preference for the formation of neutron-proton correlations (over proton-proton and neutron-neutron) in asymmetric nuclei. I will also compare results with on-going data mining efforts in older helium-3 data and discuss future avenues for studying the A=3 system.

December 5, 2024 4:00PM

CFNS Seminar: A High Luminosity Polarized Helium-3 target for various experiments in Halls A and C of Jefferson Lab
Speaker: Arun Tadepalli (Jlab)
Location:Stony Brook University - Room C-120
Slides
Abstract: The A1n, d2n, GEn-II and A_LL experiments at Jefferson lab utilized a high lu minosity polarized 3^He target to make precise measurements at high x and/or Q^2 settings. This polarized 3^He target consists of a pumping chamber (where polarization of He3 takes place), a target chamber (where e- beam interacts with the target material) and transfer tubes (which facilitate a convective flow of the polarized material). Helium-3 gas at ~8 atm pressure is filled into these glass cells along with Rb-K alkali mixture and high power narrow band diode lasers are used for polarizing the 3^He using a Spin Exchange Optical Pumping (SEOP) based technique. The target system used in the experiment includes Helmholtz coils to create a holding field that determines the direction of polarization for the 3^He nuclei. Two polarimetry techniques are used to determine the absolute (EPR) and relative (EPR) polarization during production running. Physics goals of these experiments and the overall target performance will be discussed in this talk.

November 14, 2024

4:00PM

CFNS Seminar: All order factorization for virtual Compton scattering at next-to-leading power
Speaker: Jakob Schönleber (BNL)
Location:Stony Brook University - Room C-120 Recording
Slides
Abstract: We discuss all-order factorization for the virtual Compton process at next-to-leading power (NLP) in the $\Lambda_{\rm QCD}/Q$ and $\sqrt{-t}/Q$ expansion (twist-3), both in the double-deeply-virtual case and the single-deeply-virtual case. We use the soft-collinear effective theory (SCET) as the main theoretical tool. We conclude that collinear factorization holds in the double-deeply virtual case, where both photons are far off-shell.The agreement is found with the known results for the hard matching coefficients at leading order $\alpha_s^0$, and we can therefore connect the traditional approach with SCET. In the single-deeply-virtual case, commonly called deeply virtual Compton scattering (DVCS), the contribution of non-target collinear regions complicates the factorization. These include momentum modes collinear to the real photon and (ultra)soft interactions between the photon-collinear and target-collinear modes. However, such contributions appear only for the transversely polarized virtual photon at the NLP accuracy and in fact it is the only NLP $\sim (\Lambda_{\rm QCD}/Q)^1 \sim (\sqrt{-t}/Q)^1$ contribution in that case. We therefore conclude that the DVCS amplitude for a longitudinally polarized virtual photon, where the leading power $\sim (\Lambda_{\rm QCD}/Q)^0 \sim (\sqrt{-t}/Q)^0$ contribution vanishes, is free of non-target collinear contributions and the collinear factorization in terms of twist-3 GPDs holds in that case as well. 

October 10, 2024

4:00PM

CFNS Seminar: Tunneling in string breaking and implications for hadronization
Speaker: Laura Batini (Heidelberg University
Location:Stony Brook University - Room C-120 Recording

Abstract: In this talk I will discuss particle production and string-breaking dynamics in high-energy collisions of a receding electron-positron pair using the bosonized formulation of the massive Schwinger Model (Quantum Electrodynamics in 1+1 spacetime dimensions) as an effective model for exploring QCD. The resulting particle density per rapidity interval for large masses can be fitted using a Boltzmann factor, where the temperature can be related to the hadronization temperature in QCD. Lastly, I will discuss the possibility of an analog quantum simulation of the massive Schwinger model using ultracold atoms, explicitly matching the potential of the Schwinger model to the effective potential for the relative phase of two linearly coupled Bose-Einstein condensates.

Slides

October 3, 2024

4:00 PM

CFNS Seminar: Exploring Hadron Dynamics with the Polarized Drell-Yan Process at Fermilab: Current Progress and Future Directions
Speaker: Ievgen Lavrukhin (University of Michigan)
Location: Stony Brook University - Room C-120 Slides

Abstract:  The Fermi National Accelerator Laboratory has a long history of study-ing hadron structure through fixed-target Drell-Yan experiments. The currentSpinQuest experiment aims to perform the first Sivers function measurementon sea quarks by utilizing transverse single-spin asymmetry (TSSA) measuredin the Drell-Yan process to provide evidence for non-zero orbital angular momentum of light antiquarks in the nucleon. It employs a high-intensity 120-GeVproton beam colliding with transversely polarized NH3 and ND3 cryogenic targets, along with a forward angle spectrometer that detects pairs of positive andnegative muons from Drell-Yan production. Due to the similar kinematic cov-erage, these measurements, in combination with the future Semi-Inclusive DeepInelastic Scattering (SIDIS) program at the Electron-Ion Collider, will allow totest a fundamental prediction of QCD, known as the the “sign change” of theSivers functions. In this talk, I will discuss the current status and progress of the SpinQuest experiment, as well as future measurements with a tensor-polarized Spin-1 target.

September, 12 2024

4:00 PM

CFNS Seminar: CD in non-inertial frames: effects of vorticity and acceleration on thermodynamics and phase structure of quark-gluon plasma
Speaker: Maxim Chernodub (Institut Denis Poisson, CNRS, Tours, France)
Location: Stony Brook University - Room C-120 Recording

Abstract: When relativistic heavy ions collide, they experience a rapid deceleration due to strong interaction forces between the colliding nuclei. In the process of deceleration, the initial kinetic energy of the ions gets transferred to a pre-equilibrium gluon-rich droplet, which subsequently thermalizes to a rapidly expanding fireball of quark-gluon plasma. Non-central collisions create plasma in a highly vortical (rotating) state, reflecting a large mechanical angular momentum carried by the initial nuclei. We discuss several topics related to accelerating and, separately, rotating (quark-)gluon matter, mainly based on the first-principle numerical simulations. We present the first numerical Monte Carlo results on the phase diagram of accelerating gluon plasma. We also point out the controversies in the current literature on the effect of vorticity on the phase diagram of QCD and discuss the negativity of the moment of inertia of the quark-gluon plasma in a narrow but phenomenologically interesting range of temperatures above the phase transition, violation Tolman-Ehrenfest law due to conformal anomaly and associated strong inhomogeneities of rotating plasma, as well as the signatures of an exotic negative Barnett (spin-vortical coupling) effect for gluons.
Slides

September 5, 2024

4:00 PM

CFNS Seminar: Puzzle for the Vector Meson Threshold Photoproduction
Speaker: Igor Strakovsky -The George Washington University
Location: Stony Brook University - Room C-120 Slides

August 22, 2024

4:00 PM

CFNS Seminar: Spin-orbit entanglement in QCD
Speaker: Yoshitaka Hatta
Location: Stony Brook University - Room C-120 Recording

Abstract: Spin-orbit coupling is a ubiquitous phenomenon across many subfields of physics and chemistry. I will discuss the nature of the spin-orbit coupling of quarks and gluons inside the nucleon. In the first part, I derive rigorous QCD relations for the PDFs describing the quark and gluon spin-orbit correlations. I derive a new momentum sum rule which can be regarded as the momentum version of the Jaffe-Manohar spin sum rule and explain its physical interpretation. I also discuss how the correlation can be measured at the future EIC.  In the second part, I explore possible connections to quantum information science. I show that individual quarks and gluons at small-x can be regarded as Bell states in which qubits in the spin and orbital angular momentum spaces are maximally entangled. I then discuss whether a similar interpretation is possible for partons with generic values of x.    Slides