CFNS Ad-hoc Workshop: Target fragmentation and diffraction physics with novel processes: Ultraperipheral, electron-ion, and hadron collisions
On-line meeting
The workshop is conducted on-line via ZOOM. The link for the connection is [ZOOM link].
Target fragmentation in deep-inelastic processes is emerging as a new field of study in hadronic and nuclear physics. Nucleon fragmentation in ep/γp/pp scattering provides new possibilities for measuring the spin/flavor decomposition of partonic structure and gives insight into multiparton correlations and hadronization dynamics (diquark fragmentation, quantum number transport). An important special case is diffractive scattering (rapidity gap events), where the nucleon remains intact or dissociates in a low-mass hadronic state. Nuclear fragmentation in eA/γA/pA scattering provides critical information on the nuclear configuration during the high-energy process (spectator tagging, centrality) and can be used to study nuclear final-state interactions and hadronization dynamics.
Target fragmentation measurements are performed in fixed-target (JLab, COMPASS, HERMES, earlier experiments) and collider experiments (HERA, RHIC, LHC, EIC) over a wide range of energy and momentum transfers, and with various hard processes probing the hadron (DIS, jets, heavy flavor production). In collider experiments the target fragments or diffractive protons/nuclei are detected with forward detectors integrated into the interaction region. The forward detection capabilities of the EIC offer excellent prospects for target fragmentation physics and have been explored and documented in the recent Yellow Report.
The workshop will review the physics opportunities in target fragmentation measurements in collider and fixed-target experiments. The goal is to formulate a coherent program combining the results of different experiments (energy range, type of probe) and define the context and objectives for target fragmentation measurements at EIC. The workshop will focus in particular on the following new directions:
- Target fragmentation and diffraction with ultraperipheral pA/AA collisions (UPC). UPC at LHC reach the highest CM energies in electromagnetic scattering and induce hard processes identified by final states (dijets, heavy flavors). Target fragmentation can be measured with the present LHC forward and far-forward detectors. UPC and EIC are complementary (collision energy, photo vs. electroproduction) and could be combined to a comprehensive program of target fragmentation and diffraction
- Nucleon fragmentation with variable energies and probes. Understanding of the dynamics of nucleon fragmentation in hard processes remains very limited. Existing data on leading proton/neutron production in DIS leave open many basic questions (e.g. baryon number transport). Progress could be made by: (i) Performing proton fragmentation studies with LHC data on leading proton/neutron production in pp collisions with hard processes, including correlations of the forward observables with the central event. The LHC pp data complement the HERA ep DIS data; their combination would broaden the basis for fragmentation studies. (ii) Exploring the energy dependence of nucleon fragmentation by combining DIS data from collider and fixed-target experiments, esp. the forthcoming JLab12 data. These studies could be performed in the next years and will sharpen the questions to be addressed in target fragmentation and diffraction measurements at the EIC.
- Nuclear breakup in high-energy processes. Measurements of nuclear breakup in DIS processes at EIC have many interesting physics applications such as spectator tagging with light ions (D, 3He), centrality selection in eA/γA collisions with heavy ions, and the identification of coherent nuclear scattering through veto detection. These applications rely on models of the nuclear breakup describing the energy/momentum/particle injection by the DIS process and the subsequent evolution of the nuclear system. An important question is how these models could be tested and improved using data from other high-energy processes (UPC, pA) before the start of EIC operations.
The workshop brings together theoretical and experimental researchers in quantum chromodynamics and hadron structure, high-energy ep/γp/pp scattering, ultraperipheral pA/AA collisions, nuclear breakup, and detector development, for an in-depth discussion of these topics.
The workshop is conducted in on-line format. The sessions are scheduled for 09:00-16:00 ET to allow for simultaneous participation from European and US timezones. Extensive time is reserved for topical discussions.
The previous 2020 CFNS Workshop "Target fragmentation physics with EIC" reviewed target fragmentation physics from a general perspective and documented the interest in future EIC measurements. The new workshop here continues this effort and focuses on the specific new developments described above.
Abhay Deshpande
Adrian Dumitru
Alessia Bruni
Alexander Jentsch
Alexei Larionov
Alfredo Ferrari
Andrei Afanasev
Aram Kotzinian
Arjun Kumar
Barak Schmookler
Bjoern Schenke
Carlos Bertulani
Charles Hyde
Charles Joseph Naïm
Chiara Oppedisano
Christian Weiss
Christopher Dilks
Cole Le Mahieu
Daniel Tapia Takaki
Debasish Das
Deeparna Bhattacharyya
Dien Nguyen
E. C. Aschenauer
Fredrick Olness
Hamlet Mkrtchyan
Harleen Dahiya
Harut Avagyan
Henry Klest
Janusz Chwastowski
John Dainton
Juan Marquez
Kevin Adkins
M. Gabriel Santiago
Marius Utheim
Mariusz Przybycien
Mark Baker
Mark Strikman
Marta Ruspa
Martin Hentschinski
Michael Albrow
Michael Murray
MIHIR HEMANTKUMAR PATEL
Mriganka Mouli Mondal
Narinder Kumar
Nicole Lewis
Or Hen
Patrizia Rossi
Pete Markowitz
Peter Steinberg
Prithwish Tribedy
Priyanka Boora
Quan Wang
Rainer Schicker
Rajeev Singh
Riccardo Longo
Ronan McNulty
Sebouh Paul
Shunzo Kumano
Siddharth Jain
Spencer Klein
Ted Rogers
Vadim Guzey
Victor Paulo Goncalves
Wei Li
William Schmidke
Wim Cosyn
Wlodek Guryn
Xiaoxuan Chu
Yang-Ting Chien
Yuji Goto
Zhangbu Xu
Zhoudunming Tu
Zuhal Seyma Demiroglu