Transverse Momentum Dependence of Semi-Inclusive Pion and Kaon Production E : Spokespersons Peter Bosted, Rolf Ent, Hamlet Mkrtchyan 25.5 days at 11.0 GeV & 6.5 days at 8.8 GeV = 32 days total Goal: Map the P T dependence (P T ~  < 0.5 GeV) of  + and  - production off proton and deuteron targets to study the k T dependence of (unpolarized) up and down quarks Not much is known about the orbital motion of partons Significant net orbital angular momentum of valence quarks implies significant transverse momentum of quarks Constrain k T dependence of up and down quarks separately 1) Probe  + and  - final states 2) Use both proton and neutron (d) targets 3) Combination allows, in principle, separation of quark width from fragmentation widths (if sea quark contributions small)

PAC37 : “Even if concerns remain that the experimental coverage in the full multi- dimensional space may be too limited to obtain integrated or weighted observables that can be theoretically interpreted, the cross sections are such basic tests of the understanding of SIDIS at 11 GeV kinematics that they will play a critical role in establishing the entire SIDIS program of studying the partonic structure of the nucleon. In particular they complement the CLAS12 measurements in areas where the precision of spectrometer experiments is essential, being able to separate P T and  - dependence for small P T. The PAC strongly recommends that these measurements occur in the early years of 12 GeV operation.” E : basic cross section measurements at low P T Suggested as possible “commissioning experiment” (albeit more realistically the second one due to the implicit need for Particle Identification detectors)  Can have large science impact  Prerequisite to other JLab experiments

E Collaboration Contributions Spokespersons: Hamlet Mkrtchyan, Peter Bosted, Rolf Ent Collaboration: ANSL (Yerevan), JLab, Hampton, W&M, CUA, JMU, Regina, NCA&T, UVa, Duke/TUNL, MSU, Xavier, Pavia This represents ALL detector components considered for the base SHMS plus the additional aerogel detector system. Collaboration has also wide experience in commissioning of magnetic spectrometers and beam line components.

E is an OPEN Collaboration Our belief is that any experiment should be open for all interested scientists to join, regardless if it is commissioning or not.

E Readiness The collaboration has a proven track record to be ready for experiments well in time Historically, hardware responsibilities of the Yerevan group are the first ones to be ready (HMS calorimeter!) The E collaboration is committed to work on a tight schedule to get the experiment ready to run, and has shown to have the capability for this both at Jefferson Lab and elsewhere (e.g., SLAC End Station A). The collaboration includes several spectrometer experts. Given the Hall C/E experience, analysis tools for this experiment are already in hand allowing for a speedy return on preliminary and final results.

E Features + Expertise gained with E Analysis tools ready + Ratio measurement  not very sensitive to kinematics + Standard energies ( GeV, 8.8 GeV) + Standard targets (10 cm LH2 and LD2, dummy)  A beam current, and flexible + Expertise with commissioning PId detectors - Requires Particle Identification for  - Requires Aerogel Detector commissioning and inclusion - Loose 5 days of data taking with E  Loss of overall beam time of ~2 days - 11 GeV may be high in demand at start of accelerator (likely not an issue with ongoing 3-way split work)

Benefits to Hall C and subsequent experiments High scientific impact experiment for Hall C to show off Critical role for subsequent SIDIS program  likely many followup proposals  E was the first SIDIS experiment ever approved at JLab, with now an avalanche of SIDIS experiments! All capabilities of SHMS will have been commissioned Seems a must before Hall C’s series of L/T separations

Summary of Pros and Cons + ratio measurement + not sensitive to early beam issues + high scientific impact + universities constructing SHMS detectors involved + (very) experienced collaboration in commissioning + all systems commissioned at end of E requires particle identification (both a pro and con…) - lose benefit of overlap with E needs 11 GeV beam that may be in demand if 3-way split work would be delayed