Abstract

We are proposing a comprehensive program to study transverse momentum dependence of valence quark transverse and longitudinal spin distributions through mea- surements of spin-azimuthal asymmetries in semi-inclusive electroproduction of kaons using the upgraded JLab 11 GeV polarized electron beam and the CLAS12 detector with longitudinally polarized proton and deuteron targets. Main objectives include studies of correlations of the transverse spin of quarks with their transverse momen- tum, leading to observable spin and azimuthal asymmetries. The measurement of the sin 2_ azimuthal moment of the semi-inclusive production of hadrons in DIS with lon- gitudinally polarized targets, in particular will provide direct information on spin-orbit correlations by measuring the leading twist transverse momentum dependent (TMD) parton distributions related to the interference between states with different orbital momenta. Measurements with kaons are complementary to measurements with pions and will provide additional information on the Collins fragmentation mechanism. The PT dependence of the double spin asymmetry will provide additional information on the flavor and polarization dependence of transverse momentum dependence of helicity distributions of quarks, providing complementary to SSA measurements access to spin-orbit correlations. The x, z, PT and Q2 dependences of the sin 2_ and sin _ mo- ments will be studied to probe the underlying T-odd distribution and fragmentation functions. The experiment will use the upgraded CLAS12 detector, 11 GeV highly polarized electron beam and longitudinally polarized solid ammonia targets (NH3 and ND3). Kaon identification in the complete kinematic range will be done by the proposed CLAS12-RICH proximity-focusing detector. The large acceptance of CLAS12 would allow simultaneous detection of the scattered electrons and leading hadrons from the hadronization of the struck quark, providing information on its flavor and transverse momentum. We request 30 days of running on NH3 and 50 days of running on ND3 (or possibly Li D or HD), including about 20% overhead for target anneals, polarization reversal, and auxiliary measurements. This measurement will simultaneously run with already appro ved measurements using pion electroproduction.

H. Avakian, A. Bacchetta, V.D. Burkert, L.Elouadrhiri, V. Kubarovsky, S Stepanyan E. Cisbani, F. Cusanno, F. Garibaldi, S. Frullani, P. Rossi†, E. De Sanctis, L. Hovsepyan, M. Mirazita, and S. Anefalos Pereira, K. Hafidi, J. Arrington, P. Dupr´e, D. F. Geesaman, R. J. Holt, D. H. Potterveld, P. E. Reimer, P. Solvignon K. Griffioen, Bo Zhao, M. Aghasyan, S.E. Kuhn, Z.-E. Meziani, B. Sawatzky, A. Lukhanin, D. Ireland, R. Kaiser, K. Livingston, D. MacGregor, G. Rosner, B. Seitz, K. Joo, P. Schweitzer, M. Ungaro, P.F. Dalpiaz, G. Ciullo, M. Contalbrigo, F. Giordano, P. Lenisa, L. Pappalardo, A. D’Angelo, C. Schaerf, V. Vegna, R. De Leo, L. Lagamba, S. Marrone, G. Simonetti, E. Nappi, I. Vilardi, G.M. Urciuoli, M. Battaglieri, R. De Vita, V. Drozdov, M. Osipenko, M. Ripani, M. Taiuti, V. Bellini, A. Giusa, F. Mammoliti, C. Randieri, G. Russo, M.L. Sperduto, C.M. Sutera, N. Kalantarians, D. Crabb, L.C. Smith, R. Avagyan, A. Avetisyan, R. Dallakyan, S. Taroyan, F. Benmokhtar, M. Anselmino, A. Kotzinian, B. Parsamyan, A. Prokudin, M. Burkardt, B. Pasquini, L. Gamberg, G.R. Goldstein 

A 12 GeV Research Proposal to Jefferson Lab (approved by PAC 34)