General Meson SF Meeting Summary 1/19/23

PARTICIPANTS: Rolf Ent, Tobias Frederico, Craig Roberts, David Richards, Emanuel Ydrefors, Garth Huber, Gianni Salme, Love Preet, Patrick Barry, Pepe Rodriguez Quintero, Rachel Montgomery, Richard Trotta, Tanja Horn, Carlos Ayerbe-Gayoso, Stephen Kay, Tyler Hague, Wayne de Paula

DISCUSSION MATERIAL

• Pion and Proton PDF and TMDs (Tobias) - Slides
• JAM - Pion and Proton TMDs (Patrick) - Slides
• Updates from the experiment side, e.g., efforts towards pion and kaon TMD measurements with 22 GeV JLab - Slides from the 13 January 2023 Hall C Winter Meeting

SCIENCE AT THE LUMINOSITY FRONTIER: JEFFERSON LAB AT 22 GEV WORKSHOP

• Timetable: https://indico.jlab.org/event/677/

• From Meson SF: Rolf, Craig, Jianwei, Patrick, and Rachel will present

• General idea: demonstrate that Proton and Pion TMDs are different as motivation for experiment projections shown by Rachel at the Science at the high Luminosity Frontier at JLab

PION AND PROTON TMDS (Tobias et al.)

• There are qualitative features that distinguish pions and kaons

• The model presented expresses that and is readily available to use

• Motivating plots that support the experimental efforts:

• PDF vs x
• TMD - 2D colorful plots to illustrate that there is not just a phase transition in a flux tube - it actually is different for proton and pion and kaon

• Pion DA are more dilated - should be reflected in the TMD (in the kperp dependence) as well

• pion DA is broader - more support in the pion at higher x
• peaks of the proton DA are higher, pion is much broader - highlight that
• Suggestion: make the plot on a linear scale

JAM - PROTON AND PION TMDS (Patrick et al.)

• Presentation highlights that there are differences between proton and pion TMDs and there is a significant scientific motivation for measuring the outgoing pion in TDIS to get an observable sensitive to the pion TMD

• Results show that in bT space the pion and proton look different

• Looking at average bT for a given x one can see that (for x-range: 0.3-0.6 for which data for both are available)

• up quark in proton is bigger than that of the pion
• in this range the <bT|x> for the pion is smaller than that for the proton
• both are confined in the bound system (less than the radius)

• Q&A: For the radii shown, should these be scaled to transverse space? Typically transverse radii are smaller

• Q&A: are the trends shown for the TMDs a reflection of Lambda_QCD?

EXPERIMENTAL EFFORTS

• Looking at the slides from the Hall C Winter Meeting in January 2023

• Four plots of interest

• SF/PDF vs xpi/xk
• xpi vs Wpi^2 for t=0.05
• xsec/multiplicity SIDIS vs. pT^2
• Layout of the experiment

• The ongoing efforts show that one can get reasonable quality data for pion/kaon

• PDF: higher energy JLab provides more phase space at high x and also increases the coverage down to low x
• TMD/SIDIS: based on the studies it is possible to measure pion TMDs at 22 GeV there seems to be enough luminosity to do it - get good coverage for a reasonable measurement. Note that at 11 GeV there is not enough phase space.

• Overlap between 11 GeV and 22 GeV - highlight that

• suggestion: illustrate better the overlap that shows one gets both low and high x reach, i.e., at 22 GeV one does not only get low x access

• Ongoing effort: projections for kaons

NEXT MEETING: THURSDAY 23 FEBRUARY AT 9AM ET

• Recap of 22 GeV JLab WS
• Craig et al. on TMD work