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ID 33881
file
creator
Ohno, Hiroshi
Aoki, Sinya
Ejiri, Shinji
Kanaya, Kazuyuki
Maezawa, Yu
Saito, Hana
WHOT-QCD Collaboration
abstract
We propose a method to evaluate spectral functions on the lattice based on a variational method. On a lattice with a finite spatial extent, spectral functions consist of discrete spectra only. Adopting a variational method, we calculate the locations and the heights of spectral functions at low-lying discrete spectra. We first test the method in the case of analytically solvable free Wilson quarks at zero and finite temperatures and confirm that the method well reproduces the analytic results for low-lying spectra. We find that we can systematically improve the results by increasing the number of trial states. We then apply the method to calculate the charmonium spectral functions for S and P-wave states at zero-temperature in quenched QCD and compare the results with those obtained using the conventional maximum entropy method (MEM). The results for the ground state are consistent with the location and the area of the first peak in spectral functions from the MEM, while the variational method leads to a mass which is closer to the experimental value for the first excited state. We also investigate the temperature dependence of the spectral functions for S-wave states below and above Tc. We obtain no clear evidences for dissociation of J/ψ and ηc up to 1.4Tc.
journal title
Physical Review D
volume
Volume 84
issue
Issue 9
start page
094504-1
end page
094504-13
date of issued
2011
publisher
American Physical Society
issn
1550-7998
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
(c) 2011 American Physical Society
relation url
department
Graduate School of Education