introduction form factors and observables numerical results of lattice simulation
DESCRIPTION
格子 QCD による 核子の一般化形状因子と クォーク角運動量の解析. Munehisa Ohtani ( Univ. Regensburg ) for QCDSF with D. Br ö mmel, M. G ö ckeler, Ph. H ä gler, R. Horsley, Y. Nakamura, D. Pleiter, P.E.L. Rakow, A. Sch ä fer, G. Schierholz, - PowerPoint PPT PresentationTRANSCRIPT
• Introduction • Form Factors and Observables • Numerical results of lattice simulation - Axial FFs and quark spin - 2nd Moments of GPD(vector) and total angular momentum• Summary
格子格子 QCDQCD による 核子の一般化形状因子とによる 核子の一般化形状因子とクォーク角運動量の解析クォーク角運動量の解析
20 Nov. 横断研究会 @ KEK
Munehisa Ohtani (Univ. Regensburg ) for
QCDSF
with D. Brömmel, M. Göckeler, Ph. Hägler, R. Horsley, Y. Nakamura, D. Pleiter, P.E.L. Rakow, A. Schäfer, G. Schierholz, W. Schroers, H. Stüben, J.M. Zanotti
IntroductionIntroduction
H, E, …P P'
x+ x -
momentum transfer squared:
t = (P' - P)2
longitudinal mt. transfer:
- n ·
Generalized Parton Distributions of Nucleon
Non perturbative study on Nucleon structure
q q'
Generalized Parton DistributionsGeneralized Parton Distributions
PDF q(x) q(x) q(x)
Fourier transf.
Quark density in b plane
q(x, b2) = d2 e–i b H (x, , )
GPDs
= H (x,0,0) = H (x,0,0) = HT(x,0,0) forward
limit
Form Factors
F1(t) = dx H (x, , t)
GA(t) = dx H (x, , t)
GT(t) = dx HT(x, , t)
local limit
J q = 1/2 dx x (H(x, , 0) + E(x, , 0)) u+d 1/2 ( A20 + B20 )
s q = 1/2 dx H(x, , 0)u+d 1/2 A20
Angular momentum
as moments in the forward limit
Moments of GPDMoments of GPD: : Generalized Form Factors Generalized Form Factors
An,2k , Bn,2k , Cn are related to P |q DDn}q |P'
X.-D.Ji, J.Phys.G24(1998)1181 Polynomiality
LHPC, PRD68(2003)034505
Calculate ratio of 2pt & 3pt correlation functions on lattice
Extract GFF
GFF and physical quantitiesGFF and physical quantities
A10 B10u-d
@ t = 0
Slope, mpole
Q
r 2 EM mV2
Vector Meson Dominance ?
PCAC &G-T relation
Tensor Meson Dominance ?
experiments · eN scattering
A10
u-d
gA gP
r 2 A m
A10u+d
2 s q
B10u-d
· N scattering· pion electroproduction· muon capture
A20 B20
x q2 J q x q
mf2 , ma2 ?
· DVCS - spin asymmetry - charge asymmetry
Simulation parametersSimulation parameters
Nf =2 Wilson fermions w/ clover improvement
# of config: 400-2200 for each(,)
Physical unit translated by r0
c / a
O(a) improved operators
non-perturbative renormalization into MS @ = 2 GeV
1.3470.9560.670
0.0856163 32〃 〃
〃〃
0.134200.135000.13550
5.20mGeVa [fm]volume
5.25
5.29
5.40
0.134600.135200.135750.136000.134000.135000.135500.135900.136200.13632
0.135000.135600.136100.136250.13640
163 32〃
243 48〃
243 48〃〃〃
323 64
0.0794
0.0753
0.0672
1.2250.9490.6350.457
1.5111.1020.8570.6290.4140.345
1.1830.9170.6480.5590.450
243 48〃〃〃〃〃
V.Bernard et.al. J.Phys.G 28(2002)R1
cf. A10u-d
from expt: p + e e' + + n
t dependence of Axial Form Factort dependence of Axial Form Factor
t [GeV2]
Dipole form:
A10 22 )/1(
#
Amt
A10u+d (t) with = 5.29,= 1.3632
0.402 0.024 (@ m= .14GeV)
Chiral extrapolation and quark spinChiral extrapolation and quark spin
A10u+d (t=0) 2 s u+d
= u+d
HERMES,
PRD75(2007)012007
Heavy Baryon Chiral Perturbation Theory
M.Diehl, A.Manashov, A.Schäfer, EPJ.A 29(2006)
m[GeV]
Strong m dependenceby “chiral log” term
t dependence of the 2t dependence of the 2ndnd Moments Moments
t [GeV2]
A20u-d (t), B20
u-d (t) and C20u-d (t) with = 5.29,= 1.3632
Moments of GPD: AMoments of GPD: A1010 vs. A vs. A2020 An0
u+d (t)/ An0u+d (0) with = 5.29,= 1.3632
t [GeV2]
x ~ 1 contribution in A20
broader tail of A20 in t
Dipole mass of ADipole mass of A20 20 and tensor mesonand tensor meson
mD[GeV]
in CQSM for comparison K. Goeke et. al., PRC75(2007)
Observedmass of f2
Dipole form:
A20 x .
(1 t / mD2)2
Generalized Form Factors in Chiral PerturbationGeneralized Form Factors in Chiral Perturbation M.Dorati, T.A.Gail and T.R.Hemmert, nucl-th/0703073
3 param. in each GFFs t dependence via
AA2020u+du+d(t ) and covariantized Baryon ChPT(t ) and covariantized Baryon ChPT
Chiral extrapolation of AChiral extrapolation of A2020u+du+d(t =0)(t =0)
A20u+d (t=0)
x u+d 0.572 0.012
(@ m= .14GeV)
CTEQ6 @2 = 4GeV2
M.Dorati et.al. nucl-th/0703073
m[GeV]
AA2020u-du-d(t ) and covariantized Baryon ChPT(t ) and covariantized Baryon ChPT
Chiral extrapolation of AChiral extrapolation of A2020u-du-d(t =0)(t =0)
A20u-d (t=0)
x u-d 0.198 0.008 (@ m= .14GeV)
m[GeV]
Strong m dependenceby “chiral log” term
CTEQ6 @2 = 4GeV2
Dipole fit and forward limit of BDipole fit and forward limit of B2020u,du,d(t )(t )
B20q (t)
t [GeV2]
in CQSM
J u+d = 1/2
x u+d = 1 ) no dynamical gluon
2 J q x qt 0
K.Goeke et. al., PRC75(2007)in CQSM for comparison
BB2020u+du+d(( tt ) and covariantized Baryon ChPT) and covariantized Baryon ChPT
Chiral extrapolation of BChiral extrapolation of B2020u+du+d(0)(0)
B20u+d (0)
B20u+d (0) 0.120 0.023 (@ m= .14GeV)
m[GeV]
Strong m dependenceby “chiral log” term
BB2020u-du-d(t ) and covariantized Baryon ChPT(t ) and covariantized Baryon ChPT
Chiral extrapolation of BChiral extrapolation of B2020u-du-d(0)(0)
B20u-d (0)
B20u-d (0) 0.269 0.020 (@ m= .14GeV)
m[GeV]
m[GeV]
Chiral extrapolation of JChiral extrapolation of Ju u ,, JJdd
Ji’s sum rule : J q = 1/2 [ A20q (0) +B20
q(0) ]
J u 0.230 0.008
J d 0.004 0.008
(@ m= .14GeV)
decomposition of quark angular momentumdecomposition of quark angular momentum
m[GeV]
J u+d = 1/2 [ A20u+d (0) +B20
u+d(0) ]
s u+d = 1/2 A20u+d (0)
; Lu+d = J u+d - s u+d
J u+d 0.226 0.013
s u+d 0.201 0.024
L u+d 0.025 0.027
(@ m= .14GeV)
Summary and outlookSummary and outlook
lattice simulation of moments of Generaized Parton Distribution spin content, transverse quark distribution, DVCS,…
dipole mass of A20 is comparable with tensor meson mass.
A20u-d and B20
u+d have strong “chiral log” corrections.
Chiral extrapolation of A20 (0) & B20 (0) via BChPT nucl-th/0703073 leads J u
0.230 0.008 J d
0.004 0.008
as a preliminary.
lighter m, larger volume (for t 0), Finite size corrections, Continuum limit, disconnected diagram, Chirally improved fermions, higher twist, angular momentum of gluon, …
J u+d 0.226 0.013
s u+d 0.201 0.024 (@
m= .14GeV)
L u+d 0.025 0.027