Public Abstract

DE-FG02-93ER40771: THEORETICAL STUDIES IN HIGH-ENERGY NUCLEAR PHYSICS

Award Status: Active

Institution: The Pennsylvania State University, University Park, PA
UEI: NPM2J7MSCF61
DUNS: 003403953

Most Recent Award Date: 12/19/2024
Number of Support Periods: 31
PM: Morreale, Astrid

Current Budget Period: 01/01/2023 - 05/31/2025
Current Project Period: 01/01/2022 - 05/31/2025
PI: Strikman, Mark

Supplement Budget Period: N/A

Public Abstract

Theoretical Studies in Higher Energy Nuclear Physics Mark Strikman, Pennsylvania State University (principal investigator) Abstract: At high four momentum resolution nucleon is known to be described as a system of quarks and gluons. One expects that in a similar kinematics quark – gluon degrees of freedom should be manifested in the structure of nuclei as well. It is natural to expect that in nuclei these effects should be maximal in configurations where two/ three nucleons come close together (short-range correlations, SRC). Consequently, we focus our studies on investigation of hard lepton and hadron induced phenomena with nucleons and nuclei. We are developing new theoretical tools for describing and resolving quark-gluon structure of hadrons and nuclei. The direct observation of two nucleon SRCs in the last decade in the processes we suggested long time ago has confirmed effectiveness of using hard nuclear reactions for probing structure of two nucleon SRCs. Hence, we are developing methods for investigating three nucleon SRCs in hard processes, as well as identifying processes which would allow a direct observation of non–nucleonic degrees of freedom in nuclei. Due to complexity of the dynamics of interaction with nucleons which are close together it is critical to measure properties of SRC using different processes and testing factorization into wave (spectral) function of a nucleus and the interaction blocks. Accordingly, we are developing tool kits of novel processes which could be investigated in electron – nucleus collisions at Jlab12 and as well as using hadron beams at J-Parc (Japan), FAIR (Germany), CERN. Understanding of SRC structure on quark – gluon level is impossible without a better understanding of the nucleon structure. Hence, we introduced and studied several classes of reactions which are sensitive to double parton densities as well as to the fluctuations of the strength of the projectile interaction with nucleons. At collider energies we found possible manifestations of the color fluctuation phenomena both at the LHC and RHIC in the centrality dependence of the rate of jet production in the kinematics in which progenitor quark carries large fraction of the proton momentum. We find a relationship of this phenomenon and the mechanism of emergence of non-nucleonic degrees of freedom in nuclei. We are actively involved in the studies of various Quantum Chromodynamics phenomena at the LHC. Special attention is paid to development of the theory of high energy photon – nucleus interactions which can be tested in the ultraperipheral collisions at the LHC. Such studies serve as a forerunner of the corresponding measurements at the Electron – Ion collider. We also continue to investigate non-linear effects in the forward hadron – nucleus scattering and planning to investigate how the post–selection effect (effective fractional energy losses) we proposed for the explanation of the suppression of the leading pion production in deuteron – gold collisions at RHIC would be manifested in large impact parameter heavy ion collisions at the LHC dominated by photon – nucleus interactions.

Theoretical Studies in Higher Energy Nuclear Physics

Mark Strikman, Pennsylvania State University (principal investigator)

Abstract:

At high four momentum resolution nucleon is known to be described as a system of quarks and gluons. One expects that in a similar kinematics quark – gluon degrees of freedom should be manifested in the structure of nuclei as well. It is natural to expect that in nuclei these effects should be maximal in configurations where two/ three nucleons come close together (short-range correlations, SRC). Consequently, we focus our studies on investigation of hard lepton and hadron induced phenomena with nucleons and nuclei. We are developing new theoretical tools for describing and resolving quark-gluon structure of hadrons and nuclei. The direct observation of two nucleon SRCs in the last decade in the processes we suggested long time ago has confirmed effectiveness of using hard nuclear reactions for probing structure of two nucleon SRCs. Hence, we are developing methods for investigating three nucleon SRCs in hard processes, as well as identifying processes which would allow a direct observation of non–nucleonic degrees of freedom in nuclei. Due to complexity of the dynamics of interaction with nucleons which are close together it is critical to measure properties of SRC using different processes and testing factorization into wave (spectral) function of a nucleus and the interaction blocks. Accordingly, we are developing tool kits of novel processes which could be investigated in electron – nucleus collisions at Jlab12 and as well as using hadron beams at J-Parc (Japan), FAIR (Germany), CERN. Understanding of SRC structure on quark – gluon level is impossible without a better understanding of the nucleon structure. Hence, we introduced and studied several classes of reactions which are sensitive to double parton densities as well as to the fluctuations of the strength of the projectile interaction with nucleons. At collider energies we found possible manifestations of the color fluctuation phenomena both at the LHC and RHIC in the centrality dependence of the rate of jet production in the kinematics in which progenitor quark carries large fraction of the proton momentum. We find a relationship of this phenomenon and the mechanism of emergence of non-nucleonic degrees of freedom in nuclei. We are actively involved in the studies of various Quantum Chromodynamics phenomena at the LHC. Special attention is paid to development of the theory of high energy photon – nucleus interactions which can be tested in the ultraperipheral collisions at the LHC. Such studies serve as a forerunner of the corresponding measurements at the Electron – Ion collider. We also continue to investigate non-linear effects in the forward hadron – nucleus scattering and planning to investigate how the post–selection effect (effective fractional energy losses) we proposed for the explanation of the suppression of the leading pion production in deuteron – gold collisions at RHIC would be manifested in large impact parameter heavy ion collisions at the LHC dominated by photon – nucleus interactions.