39461914
Heavy quark mass determination from the quarkonium ground state energy: a pole mass approach
The heavy quark pole mass in perturbation theory suffers from a renormalon caused, inherent uncertainty of O(?QCD). This fundamental difficulty of determining the pole mass to an accuracy better than the inherent uncertainty can be overcome by direct resummation of the first infrared renormalon. We show how a properly defined pole mass as well as the mass for the top and bottom quarks can be determined accurately from the O(m?s5) quarkonium ground state energy.
119348284
Constraining renormalon effects in lattice determination of heavy quark mass
The Borel summation technique of infrared renormalons is applied to the lattice determination of heavy-quark mass. With Borel summation a physical heavy-quark pole mass and binding energy of a heavy-light meson can be defined in a rigorous and calculable manner. A notable feature of the Borel summation, compared to the usual perturbative cancellation of IR renormalons, is an automatic scale isolation. The two approaches of handling renormalon divergence are compared in the B-meson as well as in an (imaginary) heavy-light meson with a mass much larger than the inverse of the lattice spacing.
11092579
Cosmological gravitino production in gauge mediated supersymmetry breaking models
Abstract We study the cosmological gravitino production in gauge mediated supersymmetry breaking models, while properly taking into account the existence of the messenger mass scale. It is found that for sizable parameter range of the model the messenger sector contribution leads to more stringent upper bound on the reheat temperature obtained from the condition that the universe should not be overclosed by relic gravitinos. However it turns out that in the limit of relatively low messenger scale and large gravitino mass, the relic gravitino mass density can be smaller than the critical density independently of the reheat temperature, suggesting the possibility in this limit to have a high reheat temperature without the dilution of gravitinos at late time.
18339659
Resummations with renormalon effects for the leading hadronic contribution to the muon (g-2)
The leading hadronic contribution to the muon (g − 2) value is calculated by considering a known dispersion integral which involves the Re+e−(s) ratio. The theoretical part stemming from the region below 1.8 GeV is calculated by using a contour integral involving the associated Adler function D(Q2). In the resummations, we account for the renormalon structure of the usual and the modified Borel transform of D(Q2) via an explicit ansatz and by employing judiciously chosen conformal transformations. This pushes the value of the leading hadronic contribution to the muon (g − 2)/2 upwards as compared to the value given by Davier and Höcker [Phys. Lett. B435 (1998) 427], and therefore diminishes the difference between the recently measured and the SM/QCD-predicted value of (g − 2). Typeset using REVTEX
14559352
Estimating higher order perturbative coefficients using Borel transform
A new method of estimating higher order perturbative coefficients is discussed. It exploits the rapid, asymptotic growth of perturbative coefficients and the information on the singularities in the complex Borel plane. A comparison with other methods is made in several Quantum Chromodynamics (QCD) expansions.
12337603
A scale-dependent cosmology for the inhomogeneous Universe
A scale-dependent cosmology is proposed in which the Robertson-Walker metric and the Einstein equation are modified in such a way that Ω 0 , H 0 and the age of the Universe all become scale-dependent. Its implications on the observational cosmology are discussed.
123683308
STRING THEORY AND DUALITIES IN THE QUANTUM DISSIPATIVE HOFSTADTER SYSTEM
We study the dualities of the quantum dissipative Hofstadter system which describes particles moving in two dimensions, subject to a uniform magnetic field, a periodic potential and a dissipative force. Using the string theory formulation, we show that the system has two kinds of dualities. The duality, previously known as the exact duality in the literature is shown to correspond to a subgroup of the T-dual symmetry group unbroken by the periodic boundary potential in string theory. The other duality is a particle–kink duality in the noncommutative open string theory which is a generalized Schmid duality in the presence of the uniform magnetic field. The kinks of the dissipative Hofstadter model are found to be noncommutative objects. The particle–kink duality, which is called previously the approximate duality, is shown to be also exact. In contrast to the previous derivation, which is based on the Coulomb gas expansion of the partition function and asserts that the duality holds only approximately in t...
125269418
Tachyon condensation, boundary state and string field theory
19450734
Rephasing invariant parametrization of flavor mixing matrices
The three-flavor mixing matrix can be parameterized by the rephasing invariants {gamma}{sub ijk}=V{sub 1i}V{sub 2j}V{sub 3k}. This formulation brings out the inherent symmetry of the problem and has some appealing features. Examples illustrating the parametrization and applications to quark mixing are presented.
118161656
The Entropy of the BTZ Black Hole and AdS/CFT Correspondence
We construct an action, which governs the dynamics of the Ba\~nados-Teitelboim-Zanelli (BTZ) black hole and perform the canonical quantization. The quantum action is given by a $SL(2,R)$ Wess-Zumino-Witten model on the boundary coupled to the classical anti-de Sitter background, representing a massless BTZ black hole. The coupling, determined by a one-cocyle condition, is found to give dominant contribution to the central charge of Virasoro algebra. The entropy of the BTZ black hole is discussed from the point view of the AdS/CFT correspondence and an explanation is given to the puzzle of black hole entropy in the BTZ case. The BTZ black hole is a quantum object and the BTZ black hole with finite mass should be considered as a quantum excitation of the massless one.
15173498
Mass matrices and their renormalization
We obtain explicitly the renormalization group equations for the quark mass matrices in terms of a set of rephasing invariant parameters. For a range of assumed high energy values for the mass ratios and mixing parameters, they are found to evolve rapidly and develop hierarchies as the energy scale decreases. To achieve the experimentally observed high degree of hierarchy, however, the introduction of new models with specific properties becomes necessary.