Upload
gloria
View
28
Download
0
Embed Size (px)
DESCRIPTION
Precision Charmed Meson Spectroscopy and Decay Constants from Chiral Fermions . Overlap Fermion on 2+1 flavor Domain Wall Fermion Configurations Charmonium and Charmed-strange Meson Spectrum and f Ds. χ QCD Collaboration: - PowerPoint PPT Presentation
Citation preview
Precision Charmed Meson Spectroscopy and Decay Constants
from Chiral Fermions
• Overlap Fermion on 2+1 flavor Domain Wall Fermion
Configurations• Charmonium and Charmed-strange Meson Spectrum and fDs
χQCD Collaboration: A. Alexandru, S.J. Dong, T. Draper, T. Doi, I. Horvath, B. Joo, F.
Lee, A. Li, KFL, R. Lewis, N. Mathur, X. Meng, T. Streuer, H. Thacker, and J.B. Zhang
YITP, Feb. 5, 2010
fD and fDs
Some desirable features:
– O(a2) error are small (e.g. spectrum).– O(m2a2) errors are small (dispersion relation, hyperfine
splitting) can include charm quark– The effective propagator is – Dc = D/(1 – D/2) is chirally symmetric, i.e. {γ5, Dc} = 0.– Dc + m is like in the continuum formalism. – Multi-mass algorithm (30 masses)– Renormalization is relatively simple (e.g. with chiral Ward
identity).
Undesirable feature:
– Numerically intensive (can be tamed with eigenmode deflation)
Overlap Fermion
1121 )()()1( maDmDD c
2+1 Flavor DWF Configurations(RBC and UKQCD)
163 x 32 x 16, a-1 =1.73 GeV (a = 0.114 fm), ml a=0.01, 0.02, 0.03, ms a=0.04
243 x 64 x 16, a-1 =1.73 GeV (a = 0.114 fm), ml a=0.005, 0.01, 0.02, 0.03, ms a=0.04
323 x 64 x 16, a-1 =2.42 GeV (a = 0.085 fm), ml a=0.004, 0.006, 0.008, ms a=0.03
Overlap on 2+1 Flavor DWF configurations with HYP SmearingMixed actionFor chirally symmetric valence, it is like partial quenching with one extra parameter in valence-sea mass (Chen, O’Connell, Walker-Loud, arXiv:0706.0035)
1 2 1 2
1 2 1 2
2
2 2
2 2
( ),
( ) ,
( ) ,
v v v v
vs v s mix
s s s s sea
sea res
m B m m
m B m m a
m B m m a
m
Determination of ρ (243 x 64 lattice) from Hyperfine Splitting
ρ=1.62 ρ=1.50
Overlap with Deflation
, , 5 ,1
*5 5
1, , ,
, 5 ,, * *
1
( , ) (1 ) | |
(0, ) | | ; (0, ) | |
( , )
|
where,
Therefore,
where,
a
| | |
(1 / 2) (1 / 2)
X =
d
( )
n
X
nHL R L R L R
i
i i
H LL R L R L R
nL R L RL
L Ri i i i i
H HL R
D m X i i
D i i D i i
X D m X
i i i iX
m m
X
except for the zero mod s.(X ) eL LL RX
Speed up with deflation and HYP smearing
No critical slowing downCan calculate for any mass except zeroMulti-mass inversion (30 masses)
16^3 x 32 24^3 x 64 32^3 x 64
w/o D D D+S res w/o D D D+S w/o D D D+S
lowmode 0 200 200 10-8 0 200 200 0 400 400
Inner iter 340 321 108 10-11 344 341 107 309 281 101
Outer iter 627 72 85 10-8 2931 147 184 4028 132 156
Overhead 5 pro 5 pro 6pro
speedup 23 51 79
5 5 5 221
( )(0, ) 1 1 1( )
nW i
Wi W iW
H bD HH cH
163 x 32 243 x 64
DS Spectrum
323 x 64, mla = 0.006, a = 0.0814 fmS.J. Dong talk
H.F. 119.4 (13) MeVm
Hyperfine Splitting of Charmonium (50 config.)
Expt: 116.5(1) MeV
2 2 22 2 2
2 2 2 2
1 2
1 3 1 1 3 log ( ) log 32 3
+ ( ) ( )
sv vvcv sv vv ss
cv
v s
g m mf m m mfm
c m c m
Sharpe and Zhang, ‘95
4 /2( , )lim ,
( , )
2
DS
S
S
m tA A PD t
D PP
A m P
Z G p tf e
m G p t
Z A Z mZ P
fDs on 323 x 64 lattice at chiral limit
fDs
fDs = 266.0 (9.5) MeV
fD
C. Aubin, Lattice ‘09
Z3 Grid Source with Low-Mode Substitution
t
H+L L
t0
i†j
t0
i†j
0H+L
HH
HL
L
+
†i j ij
Mesons
Z3 Grid: noise on 64 grid points separated by 8 lattice spacings on a time slice of 323 x 64 lattice
t t
0 t
ijk
0
i
0
H+L
H+L
H+L
†j
H
L
L
L
L
L
0 t
ijk
HHH
HHL
++†i j ij
i j k ij jk
Low-mode substitution for Baryons
Proton Correlator and Relative Errors with Low-mode Substituion (12 configurations)
3
3.5
4
1+-1++0++1 - -0 -+
3
3.5
4
Mas
s(Ge
V)
c
J /
c0c1 hc
2+1 Q C DExp .
2+1 flavorDWF+Overlap
0 flavorOverla
p
Is a tetraquark mesonium?
*0(2317)SD
0¯ ¯(1)1¯+(1)
0++(0)0+ ¯(1)1+ ¯(1)
π(137)
0+ (1/2)
ρ(770)
σ(600)
f0(980)
f0(1370)
f0(1500)
a0(980)
a0(1450)
a1(1230)
K0*(1430)
JPG(I))
M (M
eV)
a2(1320)
2+ ¯(1)
f0(1710)
K0*(800)
Beijing, 2004, page 28
Why a0(980) is not a state?
• The corresponding K0 would be ~ 1100 MeV which is 300 MeV away from both and .
• Cannot explain why a0(980) and f0(980) are narrow while σ(600) and κ(800) are broad.
• γ γ width of a0(980) and f0(980) are much smaller than expected of states.
• Large indicates
in f0(980), but cannot be in I=1 a0(980). How to explain the mass degeneracy then?
*0 (1430)K (800)
0 0(980) , (980) sf D f
ss
Our results shows scalar mass around 1400-1500 MeV, suggesting
a0(1450) is a two quark state.
)(JI PCG ),0(1 )1(1
ms
KYIS06 2006, page 30
)]0(0 )(JI ,[ PCG55
Further study is needed to check the volume dependence of the observed states.
Scattering states(Negative scattering length)
)0()0( pEpE
)1()1( pEpE
Scattering states
Possible BOUND state σ(600)?
Volume dependence of spectral weights
Volume independence suggests the observed state is an one particle state
W0
W1
0¯ ¯(1)1¯+(1)
0++(0)0+ ¯(1)1+ ¯(1)
π(137)
0+ (1/2)
ρ(770)
σ(600)
f0(980)
f0(1370)
f0(1500)
a0(980)
a0(1450)
a1(1230)
K0*(1430)
JPG(I))
M (M
eV)
a2(1320)
2+ ¯(1)
f0(1710)
K0*(800)
MesoniumsKK Kπ Mesoniumππ Mesonium
Beijing, 2004, page 33
Scalar Mesons and Glueball
0(1500)f
00 (1470)a
*0 (1430)K*
0 (1430)K
*0 (1430)K*
0 (1430)K
0 (1470)a 0 (1470)a
(800)
0(980)f0 (980)a 0 (980)a00 (980)a
(800)
(800) (800)
)( KK
)( K
0(1370)f
(600)
0(1710)fglueball
2 2q q
SummaryChiral fermions (Overlap valence on 2+1 flavor DWF configurations)Preliminary results on DS spectrum at one sea mass and one lattice spacing.Preliminary results on hyperfine splitting of charmonium, and fDs at chiral and continuum limits. Systematic errors (NLO MAPQ PT fitting)Noise grid source can reduce errors by a factor of 3 to 4. Need to observe all members of multiplets in addition to to discern tetraquark mesoniums.