Transverse Momentum Dependence of Semi-Inclusive Pion and Kaon

ProductionE12-09-017: Spokespersons Peter Bosted, Rolf Ent, Hamlet Mkrtchyan25.5 days at 11.0 GeV & 6.5 days at 8.8 GeV = 32 days total

Goal: Map the PT dependence (PT ~ L < 0.5 GeV) of p+ and p- production off proton and deuteron targets to study the kT 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 kT dependence of up and down quarks separately

1) Probe p+ and p- 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 PT and f-dependence for small PT. The PAC strongly recommends that these measurements occur in the early years of 12 GeV operation.”

E12-09-017: basic cross section measurements at low PT

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

E12-09-017 Collaboration ContributionsSpokespersons: Hamlet Mkrtchyan, Peter Bosted, Rolf EntCollaboration: 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.

E12-09-017 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.

E12-09-017 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 E12-09-017 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/E00-108 experience, analysis tools

for this experiment are already in hand allowing for a speedy return on preliminary and final results.

E12-09-017 Features+ Expertise gained with E00-108+ Analysis tools ready+ Ratio measurement not very sensitive to

kinematics+ Standard energies (25.5 days @ 11.0 GeV, 6.5 @ 8.8

GeV)+ Standard targets (10 cm LH2 and LD2, dummy)+ 10-75 mA beam current, and flexible+ Expertise with commissioning PId detectors

- Requires Particle Identification for p- Requires Aerogel Detector commissioning and

inclusion- Loose 5 days of data taking with E12-06-104

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 E00-108 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 E12-09-017

- requires particle identification (both a pro and con…)- lose benefit of overlap with E12-06-104- needs 11 GeV beam that may be in demand if 3-way split work would be

delayed