December 17, 2004 JLab Hall A Upgrade 1 Semi-Inclusive DIS --opportunities at JLab upgrade Feng Yuan RBRC, Brookhaven National Laboratory.
Post on 27-Mar-2015
216 Views
Preview:
Transcript
December 17, 2004 JLab Hall A Upgrade 1
Semi-Inclusive Semi-Inclusive DISDIS
--opportunities at JLab --opportunities at JLab upgradeupgradeFeng Yuan Feng Yuan
RBRC, Brookhaven National RBRC, Brookhaven National LaboratoryLaboratory
December 17, 2004 2JLab Hall A Upgrade
OutlineOutline IntroductionIntroduction Low PLow P?? SIDIS (TMD) SIDIS (TMD)
High PHigh P?? SIDIS (Quark-gluon SIDIS (Quark-gluon correlations)correlations)
Integrated SIDIS (Flavor Integrated SIDIS (Flavor decomposition)decomposition)
SummarySummary
December 17, 2004 3JLab Hall A Upgrade
Inclusive and Inclusive and Semi-inclusive DISSemi-inclusive DIS
Inclusive DIS:Partonic Distribution depending on the longitudinal momentum fraction
Semi-inclusive DIS:Probe additional information includingthe transverse distribution
December 17, 2004 4JLab Hall A Upgrade
Different Different PP?? Region Region
Integrate out Integrate out PP??
-- normal factorization, similar to -- normal factorization, similar to inclusive DISinclusive DIS
Large Large PP? ? ((ÀÀQCDQCD))
-- hard gluon radiation, can be calculated -- hard gluon radiation, can be calculated from perturbative QCD, factorization from perturbative QCD, factorization similar to inclusive DISsimilar to inclusive DIS
Low Low PP? ? ((»»QCDQCD))
-- nonperturbative information: new -- nonperturbative information: new factorization formulafactorization formula
? ! 12GeV
12GeV
12GeV
December 17, 2004 5JLab Hall A Upgrade
Semi-Inclusive DIS at Semi-Inclusive DIS at Low PLow P??
Transverse Momentum Dependent Transverse Momentum Dependent (TMD) Parton Distributions(TMD) Parton Distributions
Novel Single Spin AsymmetriesNovel Single Spin Asymmetries
December 17, 2004 6JLab Hall A Upgrade
TMD Parton TMD Parton DistributionsDistributions
The gauge invariant definitionThe gauge invariant definition
Belitsky, Ji, Yuan (03)
December 17, 2004 7JLab Hall A Upgrade
Polarized TMD Quark Polarized TMD Quark DistributionsDistributions
Quark
Nucleon
Unpol.
Long.
Trans.
Unpol. Long. Trans.
q(x, kq(x, k┴┴)) qqTT(x, k(x, k┴┴))
ΔqΔqLL(x, k(x, k┴┴)) ΔqΔqTT(x, k(x, k┴┴))
δq(x, kδq(x, k┴┴)) δqδqLL(x, k(x, k┴┴)) δqδqTT(x, k(x, k┴┴) ) δqδqTT'(x, k(x, k┴┴))
Boer, Mulders, Tangerman (96&98)
December 17, 2004 8JLab Hall A Upgrade
The Physics We can learn The Physics We can learn from TMDfrom TMD
Internal structure, transverse momentum dis.Internal structure, transverse momentum dis. Quark Orbital Angular MomentumQuark Orbital Angular Momentum
e.g, Siver’s function ~ the wave function e.g, Siver’s function ~ the wave function amplitude with orbital angular momentum!amplitude with orbital angular momentum! Vanishes if quarks only in s-state!Vanishes if quarks only in s-state!
Friends: Friends: Pauli Form Factor FPauli Form Factor F22(t)(t) Spin-dependent structure function gSpin-dependent structure function g22(x)(x) Generalized Parton Distribution E(x, Generalized Parton Distribution E(x, ξξ, t), t)
December 17, 2004 9JLab Hall A Upgrade
Connection between TMD Connection between TMD and GPDand GPD
Wigner distributionsWigner distributions
After integrating over After integrating over rr, one , one gets TMDgets TMD
After integrating over After integrating over kk, one , one gets Fourier transform of GPDsgets Fourier transform of GPDs
Ji: PRL91,062001(2003)
December 17, 2004 10JLab Hall A Upgrade
SIDIS Cross SectionSIDIS Cross Section At leading power of 1/Q
The structure functions depend on Q2, xB, z, Ph?
December 17, 2004 11JLab Hall A Upgrade
Low PLow P?? SIDIS SIDIS FactorizationFactorization
Ji, Ma, Yuan, hep-ph/0404183,hep-ph/0405085
December 17, 2004 12JLab Hall A Upgrade
SIDIS: at Large PSIDIS: at Large P??
Large Large PP?? SIDIS can be calculated from SIDIS can be calculated from perturbative QCDperturbative QCD
Polarized scattering will provide information Polarized scattering will provide information on the quark-gluon correlations in the on the quark-gluon correlations in the nucleonnucleon
Single Spin Asymmetry at large PSingle Spin Asymmetry at large P?? is not is not suppressed by suppressed by 1/Q1/Q, but by , but by 1/P1/P??
With enough luminosities, we could measure With enough luminosities, we could measure these asymmetries at large these asymmetries at large PP?? at JLab at JLab 12GeV12GeV??
December 17, 2004 13JLab Hall A Upgrade
SSA at Large PSSA at Large P??
Qiu-Sterman mechanismQiu-Sterman mechanism
It is suppressed by It is suppressed by 1/P1/P??
Efremov & Teryaev: 1982 & 1984Qiu & Sterman: 1991 & 1999
Quark-gluon correlations
December 17, 2004 14JLab Hall A Upgrade
Transition from Transition from Perturbative region to Perturbative region to
Nonperturbative region?Nonperturbative region? Compare different region of PCompare different region of P??
Nonperturbative TMD Perturbative region
December 17, 2004 15JLab Hall A Upgrade
SIDIS: Integrated over PSIDIS: Integrated over P??
The factorization formulas are much The factorization formulas are much simplersimpler
Flavor decomposition for (polarized) Flavor decomposition for (polarized) PDFPDFFrankfurt et al 89; Melnitchouk et al 98, HERMES, EMC…Frankfurt et al 89; Melnitchouk et al 98, HERMES, EMC…
NLO: de Florian et al 96-98; Leader et al 01; Kretzer 04NLO: de Florian et al 96-98; Leader et al 01; Kretzer 04
Altarelli et al 79 (NLO)Altarelli et al 79 (NLO)
December 17, 2004 16JLab Hall A Upgrade
Flavor Decomposition for Flavor Decomposition for PDFPDF
(Leading Order)(Leading Order) In the valence region (large x),In the valence region (large x),
Isospin relation,Isospin relation,
DDuu++=D=Ddd
--, favored, favored; ; DDuu--=D=Ddd
++, , unfavoredunfavored; ;
DDuu--<< << DDuu
++
December 17, 2004 17JLab Hall A Upgrade
“favored”
“unfavored”
Well described by leading particle ansatz
Stefan Kretzer
December 17, 2004 18JLab Hall A Upgrade
Continue,Continue,
Similarly, from the polarized Similarly, from the polarized scattering,scattering,
d/u at large x!!
December 17, 2004 19JLab Hall A Upgrade
SummarySummary
Semi-inclusive DIS at JLab upgrade Semi-inclusive DIS at JLab upgrade provides various opportunities to study provides various opportunities to study nucleon structurenucleon structure
Low Low PP?? probes TMD parton distributions probes TMD parton distributions
High High PP?? probes quark-gluon correlations probes quark-gluon correlations ??
Integrated Integrated PP?? probes flavor decomposition probes flavor decomposition of PDFs, especially for of PDFs, especially for large xlarge x quark and quark and helicity distributions.helicity distributions.
top related