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ABSTRACT: We determine mass and mixing angles of eta and eta' states using Nf=2+1+1
Wilson twisted mass lattice QCD. We describe how those flavour singlet states
need to be treated in this lattice formulation. Results are presented for three
values of the lattice spacing, a=0.061 fm, a=0.078 fm and a=0.086 fm, with
light quark masses corresponding to values of the charged pion mass in a range
of 230 to 500 MeV and fixed bare strange and charm quark mass values. We obtain
557(15)(45) MeV for the eta mass (first error statistical, second systematic)
and 44(5) degrees for the mixing angle in the quark flavour basis,
corresponding to -10(5) degrees in the octet-singlet basis.
06/2012;
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ETM collaboration,
B. Blossier,
P. Dimopoulos,
R. Frezzotti,
G. Herdoiza,
K. Jansen,
V. Lubicz,
G. Martinelli,
C. Michael,
G. C. Rossi,
A. Shindler,
S. Simula,
C. Tarantino, C. Urbach
[show abstract]
[hide abstract]
ABSTRACT: A method to extract B-physics parameters (b-quark mass and f
B
, fBs {f_{{B_s}}} decay constants) from currently available lattice data is presented and tested. The approach is based on the idea of constructing
appropriate ratios of heavy-light meson masses and decay constants, respectively, possessing a precisely known static limit,
and evaluating them at various pairs of heavy quark masses around the charm. Via a smooth interpolation in the heavy quark
mass from the easily accessible charm region to the asymptotic point, B-physics parameters are computed with a few percent (statistical + systematic) error using recently produced N
f
= 2 maximally twisted Wilson fermions data.
KeywordsLattice QCD-Quark Masses and SM Parameters-B-Physics-Heavy Quark Physics
Journal of High Energy Physics 04/2012; 2010(4):1-25. · 5.83 Impact Factor
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European Twisted Mass Collaboration,
Remi Baron,
Phillip Boucaud,
Petros Dimopoulos,
Roberto Frezzotti,
David Palao,
Giancarlo Rossi,
Federico Farchioni,
Gernot Münster,
Tobias Sudmann,
Vicent Gimenez,
Gregorio Herdoiza,
Karl Jansen,
Vittorio Lubicz,
Silvano Simula,
C. Michael,
L. Scorzato,
A. Shindler, C. Urbach,
U. Wenger
[show abstract]
[hide abstract]
ABSTRACT: We present a comprehensive investigation of light meson physics using maximally twisted mass fermions for N
f
= 2 mass-degenerate quark flavours. By employing four values of the lattice spacing, spatial lattice extents ranging from
2.0 fm to 2.5 fm and pseudo scalar masses in the range 280 ≲ m
PS ≲ 650MeV we control the major systematic effects of our calculation. This enables us to confront our N
f
= 2 data with SU(2) chiral perturbation theory and extract low energy constants of the effective chiral Lagrangian and derived
quantities, such as the light quark mass.
KeywordsLattice QCD–Quark Masses and SM Parameters–QCD
Journal of High Energy Physics 04/2012; 2010(8):1-41. · 5.83 Impact Factor
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ABSTRACT: The phase structure of zero temperature twisted mass lattice QCD is investigated. We find strong metastabilities in the plaquette observable in correspondence of which the untwisted quark mass assumes positive or negative values. We provide interpretations of this phenomenon in terms of chiral symmetry breaking and the effective potential model of Sharpe and Singleton.
European Physical Journal C 04/2012; 39(4):421-433. · 3.63 Impact Factor
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B. Blossier,
M. Brinet,
N. Carrasco,
P. Dimopoulos,
X Du,
R. Frezzotti,
V. Gimenez,
G. Herdoiza,
K. Jansen,
V. Lubicz,
D. Palao,
E. Pallante,
O. Pene,
K. Petrov,
S. Reker,
G. C. Rossi,
F. Sanfilippo,
L. Scorzato,
S. Simula, C. Urbach
[show abstract]
[hide abstract]
ABSTRACT: We present preliminary results of the non-perturbative computation of the
RI-MOM renormalisation constants in a mass-independent scheme for the action
with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our
project requires dedicated gauge ensembles with four degenerate sea quark
flavours at three lattice spacings and at several values of the standard and
twisted quark mass parameters. The RI-MOM renormalisation constants are
obtained from appropriate O(a) improved estimators extrapolated to the chiral
limit.
12/2011;
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[show abstract]
[hide abstract]
ABSTRACT: We investigate the thermal QCD transition with two flavors of maximally
twisted mass fermions for a set of pion masses, 300 MeV \textless $m_\pi$
\textless 500 MeV, and lattice spacings $a$ \textless 0.09 fm. We determine the
pseudo-critical temperatures and discuss their extrapolation to the chiral
limit using scaling forms for different universality classes, as well as the
scaling form for the magnetic equation of state. For all pion masses considered
we find resonable consistency with O(4) scaling plus leading corrections.
However, a true distinction between the O(4) scenario and a first order
scenario in the chiral limit requires lighter pions than are currently in use
in simulations of Wilson fermions.
02/2011;
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R. Baron,
B. Blossier,
P. Boucaud,
J. Carbonell,
A. Deuzeman,
V. Drach,
F. Farchioni,
V. Gimenez,
G. Herdoiza,
K. Jansen,
C. Michael,
I. Montvay,
E. Pallante,
O. Pène,
S. Reker, C. Urbach,
M. Wagner,
U. Wenger,
for the ETM Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We present results of lattice QCD simulations with mass-degenerate up and
down and mass-split strange and charm (Nf=2+1+1) dynamical quarks using Wilson
twisted mass fermions at maximal twist. The tuning of the strange and charm
quark masses is performed at three values of the lattice spacing a~0.06 fm,
a~0.08 fm and a~0.09 fm with lattice sizes ranging from L~1.9 fm to L~3.9 fm.
We perform a preliminary study of SU(2) chiral perturbation theory by combining
our lattice data from these three values of the lattice spacing.
01/2011;
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[show abstract]
[hide abstract]
ABSTRACT: We study light-quark observables by means of dynamical lattice QCD simulations using two flavours of twisted mass fermions at maximal twist. We employ chiral perturbation theory to describe our data for the pion mass and decay constant. In this way, we extract precise determinations for the low-energy constants of the effective theory as well as for the light-quark mass and the chiral condensate. Comment: 8 pages, 2 figures, presented at the XXVII International Symposium on Lattice Field Theory, July 26-31, 2009, Peking University, Beijing, China
12/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We study lattice QCD determinations of the pion mass and decay constant by means of chiral perturbation theory (ChPT). The lattice data are obtained from large scale simulations with N_f=2 flavours of twisted mass fermions at maximal twist. We perform a scaling test to the continuum limit of these data and use ChPT to perform both the chiral and the infinite volume extrapolations. Comment: 8 pages, 4 figures, presented at International Workshop on Effective Field Theories: From the Pion to the Upsilon (EFT 09), Valencia, Spain, 2-6 Feb 2009
12/2009;
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[show abstract]
[hide abstract]
ABSTRACT: In this talk we give an overview of the 3D phase diagram of two-flavour non-zero temperature lattice QCD with twisted-mass Wilson fermions and a tree-level Symanzik-improved gauge action. We present a first feasibility study at maximal twist and, for the quenched case, we demonstrate automatic O(a)-improvement to work. Comment: 7 pages, 12 figures. To appear in the Proceedings of 27th International Symposium on Lattice Field Theory (Lattice 2009), Beijing, China, July 26-31, 2009
12/2009;
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R. Baron,
B. Blossier,
P. Boucaud,
A. Deuzeman,
V. Drach,
F. Farchioni,
V. Gimenez,
G. Herdoiza,
K. Jansen,
C. Michael,
I. Montvay,
D. Palao,
E. Pallante,
O. Pène,
S. Reker, C. Urbach,
M. Wagner,
U. Wenger,
for the ETM Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We present first results from runs performed with Nf=2+1+1 flavours of dynamical twisted mass fermions at maximal twist: a degenerate light doublet and a mass split heavy doublet. An overview of the input parameters and tuning status of our ensembles is given, together with a comparison with results obtained with Nf=2 flavours. The problem of extracting the mass of the K- and D-mesons is discussed, and the tuning of the strange and charm quark masses examined. Finally we compare two methods of extracting the lattice spacings to check the consistency of our data and we present some first results of ChiPT fits in the light meson sector. Comment: 8 pages, 4 figures. Talk presented at the XXVII International Symposium on Lattice Field Theory, July 26-31 2009, Peking University, Beijing, China
11/2009;
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ETM Collaboration,
B. Blossier,
P. Dimopoulos,
R. Frezzotti,
G. Herdoiza,
K. Jansen,
V. Lubicz,
G Martinelli,
C. Michael,
G. C. Rossi,
F. Sanfilippo,
A. Shindler,
S. Simula,
C. Tarantino, C. Urbach,
M. Wagner
[show abstract]
[hide abstract]
ABSTRACT: We present a lattice QCD calculation of the heavy-light decay constants f_B and f_Bs performed with Nf=2 maximally twisted Wilson fermions, at four values of the lattice spacing. The decay constants have been also computed in the static limit and the results are used to interpolate the observables between the charm and the infinite-mass sectors, thus obtaining the value of the decay constants at the physical b quark mass. Our preliminary results are f_B=191(14) MeV, f_Bs=243(14) MeV, f_Bs/f_B=1.27(5). They are in good agreement with those obtained with a novel approach, recently proposed by our Collaboration (ETMC), based on the use of suitable ratios having an exactly known static limit. Comment: Proceedings of the 27th International Symposium on Lattice Field Theory (Lattice 2009), Beijing, China, 2009 July 26-31. 8 pages, 3 figures
11/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We review various B meson decays that require knowledge of the transverse decay constant of the b1(1235) meson. We report on an exploratory lattice QCD calculation of the transverse decay constant of the b1 meson. The lattice QCD calculations used unquenched gauge configurations, at two lattice spacings, generated with two flavours of sea quarks. The twisted mass formalism is used. Comment: 11 pages, 3 figures. Fixed some typos, updated value of one of the sum rule results
10/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We report results for the masses of the flavor nonsinglet light 0++, 1--, and 1+- mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavors of sea quarks. For the 0++ and 1+- mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the ρ meson. We test the mass dependence of the KSRF relations, between the mass, leptonic coupling constant, and strong coupling of the rho meson.
Phys. Rev. D. 09/2009; 80(5).
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[show abstract]
[hide abstract]
ABSTRACT: In this paper we propose to interpret the large discretization artifacts affecting the neutral pion mass in maximally twisted lattice QCD simulations as O(a^2) effects whose magnitude is roughly proportional to the modulus square of the (continuum) matrix element of the pseudoscalar density operator between vacuum and one-pion state. The numerical size of this quantity is determined by the dynamical mechanism of spontaneous chiral symmetry breaking and turns out to be substantially larger than its natural magnitude set by the value of Lambda_QCD. Comment: 38 pages, 1 figure, 2 tables
08/2009;
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European Twisted Mass collaboration,
B. Blossier,
P. Dimopoulos,
R. Frezzotti,
B. Haas,
G. Herdoiza,
K. Jansen,
V. Lubicz,
F. Mescia,
D. Palao,
A. Shindler,
S. Simula,
C. Tarantino, C. Urbach,
U. Wenger
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a lattice QCD calculation of the pseudoscalar meson decay constants fπ, fK, fD and fDs, performed with Nf = 2 dynamical fermions. The simulation is carried out with the tree-level improved Symanzik gauge action and with the twisted mass fermionic action at maximal twist. We have considered for the final analysis three values of the lattice spacing, a 0.10 fm, 0.09 fm and 0.07 fm, with pion masses down to mπ 270 MeV. Our results for the light meson decay constants are fK = 158.1(2.4) MeV and fK/fπ = 1.210(18). From the latter ratio, by using the experimental determination of Γ(K → μμ(γ))/Γ(π → μμ(γ)) and the average value of |Vud| from nuclear beta decays, we obtain |Vus| = 0.2222(34), in good agreement with the determination from semileptonic Kl3 decays and the unitarity constraint. For the D and Ds meson decay constants we obtain fD = 197(9) MeV, fDs = 244(8) MeV and fDs/fD = 1.24(3). Our result for fD is in good agreement with the CLEO experimental measurement. For fDs our determination is smaller than the PDG 2008 experimental average but in agreement with a recent improved measurement by CLEO at the 1.4 σ level.
Journal of High Energy Physics 07/2009; 2009(07):043. · 5.83 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: We report results for the masses of the flavour non-singlet light 0++, 1--, and 1+- mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0++ and 1+- mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the rho meson. We test the mass dependence of the KRSF relations. Comment: 35 pages, 14 figures. Added 2 references. Fixed small typos
06/2009;
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B. Blossier,
P. Dimopoulos,
R. Frezzotti,
B. Haas,
G. Herdoiza,
K. Jansen,
V. Lubicz,
F. Mescia,
D. Palao,
A. Shindler,
S. Simula,
C. Tarantino, C. Urbach,
U. Wenger,
ETM Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a lattice QCD calculation of the pseudoscalar meson decay constants fpi, fK, fD and fDs, performed with Nf=2 dynamical fermions. The simulation is carried out with the tree-level improved Symanzik gauge action and with the twisted mass fermionic action at maximal twist. We have considered for the final analysis three values of the lattice spacing, a~0.10 fm, 0.09 fm and 0.07 fm, with pion masses down to mpi~270 MeV. Our results for the light meson decay constants are fK=158.1(2.4) MeV and fK/fpi=1.210(18). From the latter ratio, by using the experimental determination of Gamma(K-->mu nu_mu (gamma))/ Gamma(pi--> mu nu_mu (gamma)) and the average value of |Vud| from nuclear beta decays, we obtain |Vus|=0.2222(34), in good agreement with the determination from semileptonic Kl3 decays and the unitarity constraint. For the D and Ds meson decay constants we obtain fD=197(9) MeV, fDs=244(8) MeV and fDs/fD=1.24(3). Our result for fD is in good agreement with the CLEO experimental measurement. For fDs our determination is smaller than the PDG 2008 experimental average but in agreement with a recent improved measurement by CLEO at the 1.4 sigma level.
05/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We compare flavour singlet and non-singlet vector mesons from first principles using lattice QCD. With N_f=2 flavours of light quark, this addresses the omega-rho mass difference. Using maximally twisted-mass lattice QCD, we are able for the first time to determine this mass difference precisely and we compare with experiment. We also discuss omega-rho mixing effects arising within QCD through the u-d quark mass difference. Comment: 12 pages 4 figures
02/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We present results for chiral extrapolations of the mass and decay constants of the rho meson. The data sets used are the n f =2 unquenched gauge configurations generated with twisted mass fermions by the European Twisted Mass Collaboration. We describe a calculation of three decay constants in charmonium and explain why they are required.
11/2008;
