118968482
Massive overlap fermions on anisotropic lattices
We formulate the massive overlap fermions on anisotropic lattices. We find that the dispersion relation for the overlap fermion resembles the continuum form in the low-momentum region once the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. Using tadpole improved perturbation theory, we establish the relation between the well-tuned parameters and the quark mass once the bare coupling is given. We argue that massive domain wall quarks might be helpful in lattice QCD studies on heavy-light hadron spectroscopy.
119273385
Symmetry and special relativity in Finsler spacetime with constant curvature
Within the framework of projective geometry, we investigate kinematics and symmetry in (alpha, beta) spacetime one special types of Finsler spacetime. The projectively flat (alpha, beta) spacetime with constant flag curvature is divided into four types. The symmetry in type A-Riemann spacetime with constant sectional curvature-is just the one in de Sitter special relativity. The symmetry in type B-locally Minkowski spacetime-is just the one in very special relativity. It is found that type C-Funk spacetime and type D-scaled Berwald's metric spacetime both possess the Lorentz group as its isometric group. The geodesic equation, algebra and dispersion relation in the (alpha, beta) spacetime are given. The corresponding invariant special relativity in the four types of (alpha, beta) spacetime contain two parameters, the speed of light and a geometrical parameter, which may relate to the new physical scale. They all reduce to Einstein's special relativity while the geometrical parameter vanishes. (C) 2012 Elsevier B.V. All rights reserved.
15016243
A Possible scenario of the Pioneer anomaly in the framework of Finsler geometry
The weak field approximation of geodesics in Randers-Finsler space is investigated. We show that a Finsler structure of Randers space corresponds to the constant and sunward anomalous acceleration demonstrated by the Pioneer 10 and 11 data. The additional term in the geodesic equation acts as "electric force", which provides the anomalous acceleration. (C) 2010 Elsevier B.V. All rights reserved.
118861755
Constraints from Type IA Supernovae on {\lambda}-CDM Model in Randers-Finsler Space
Abstract Gravitational field equations in Randers-Finsler space of approximate Berwald type are investigated. A modified Friedmann equation and a new luminosity distance-redshift relation is proposed. A best-fit to the Type Ia supernovae (SNe) observations yields that the ΩΛ in the Λ-CDM model is suppressed to almost zero. This fact indicates that the astronomical observations on the Type Ia SNe can be described well without invoking any form of dark energy. The best-fit age of the universe is given. It is in agreement with the age of our galaxy.
14726570
Massive domain wall fermions on four-dimensional anisotropic lattices
We formulate the massive domain wall fermions on anisotropic lattices. For the massive domain wall fermion, we find that the dispersion relation assumes the usual form in the low momentum region when the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. For light domain wall fermions, we verified that the chiral mode is stable against quantum fluctuations on anisotropic lattices. This calculation serves as a guidance for the tuning of the parameters in the quark action in future numerical simulations.
118130623
Quantum resonance scheme to measure the gravitational constant G
119191019
The effects of a family non-universal Z-prime boson on B--->pipi decays
Motivated by the measured large branching ratio of (the so-called ππ puzzle), we investigate the effects of a family nonuniversal Z′ model on the tree-dominated B → ππ decays. We find that the Z′ coupling parameter with a nontrivial new weak phase , which is relevant to the Z′ contributions to the QCD penguin sector △C5, is needed to reconcile the observed discrepancy. Combined with the recent fitting results from B → πK, πK* and ρK decays, the Z′ parameter spaces are severely reduced but still not excluded entirely, implying that both the "ππ" and "πK" puzzles could be accommodated simultaneously within such a family nonuniversal Z′ model.
118023575
Determination of the strong coupling $g_{B^* B\pi}$ from semi-leptonic $B\to \pi \ell \nu$ decay
According to heavy-meson chiral perturbation theory, the vector form factor $f_+(q^2)$ of exclusive semi-leptonic decay $B\to \pi \ell \nu$ is closely related, at least in the soft-pion region (i.e., $q^{2} \sim (m_B-m_{\pi})^2$), to the strong coupling $g_{B^* B\pi}$ or the normalized coupling $\hat g$. Combining the precisely measured $q^2$ spectrum of $B\to \pi \ell \nu$ decay by the BaBar and Belle collaborations with several parametrizations of the form factor $f_+(q^2)$, we can extract these couplings from the residue of the form factor at the $B^*$ pole, which relies on an extrapolation of the form factor from the semi-leptonic region to the unphysical point $q^2=m_{B^*}^2$. Comparing the extracted values with the other experimental and theoretical estimates, we can test these various form-factor parametrizations, which differ from each other by the amount of physical information embedded in. It is found that the extracted values based on the BK, BZ and BCL parametrizations are consistent with each other and roughly in agreement with the other theoretical and lattice estimates, while the BGL ansatz, featured by a spurious, unwanted pole at the threshold of the cut, gives a neatly larger value.
119277218
Two-loop QCD correction to differential semi-leptonic b→u decays in the shape-function region
Abstract We calculate the two-loop QCD correction to the form factors of on-shell b -quark decay to an energetic massless quark, which constitutes the last missing piece required for an O ( α s 2 ) determination of | V u b | from inclusive semi-leptonic B ¯ → X u l ν ¯ decays in the shape-function region.
118637791
Topological orbital ladders
Synthetic quantum orbital materials, such as the recent double-well optical lattices loaded with s and p orbital atoms [1, 2], open an avenue to exploit symmetries beyond natural crystals. Exotic superfluid states were reported for bosons. Here, we unveil a topological phase of interacting fermions on a two-leg ladder of unequal parity orbitals, derived from the experimentally realized double-well lattices by dimension reduction. Z2 topological invariant originates simply from the staggered phases of sp-orbital quantum tunneling, requiring none of the previously known mechanisms such as spin-orbit coupling or artificial gauge field. Another unique feature is that upon crossing over to two dimensions with coupled ladders, the edge modes from each ladder form a parity-protected flat band at zero energy, opening the route to strongly correlated states controlled by interactions. Experimental signatures are found in density correlations and phase transitions to trivial band and Mott insulators. The uneven double-well potential formed by laser light has been developed into a powerful tool for quantum gases by numerous groups [1–6]. For instance, controls of atoms on the sand p-orbitals of the checkerboard [1] and hexagonal [6] optical lattices have been demonstrated, and correlation between these orbitals tends to give exotic quantum states [6, 7]. Motivated by these developments, we consider a lattice of uneven double-wells where fermionic atoms are loaded up to the sand porbital levels of the shallow and deep wells respectively, as shown in Fig. 1. The spatial symmetry of the orbital wave function dictates the complex hopping amplitudes between nearby sites. Under certain circumstances, as for the uneven double wells, the orbital hopping pattern is sufficient for producing topologically nontrivial band structures [8]. We will first focus on a one-dimensional ladder system illustrated in Fig. 1b and 1c. This corresponds to the quasi-one dimensional limit of a standard double-well optical lattice, with the optical potential given by
118442016
Extracting the nuclear symmetry potential and energy from neutron-nucleus scattering data
Abstract According to the Hugenholtz–Van Hove theorem, the symmetry energy and its density slope can be decomposed uniquely in terms of the single-nucleon potential in asymmetric nuclear matter which, at normal density, can be constrained by the nucleon optical model potential extracted from analyzing the nucleon–nucleus scattering data. To more accurately extract information on the symmetry energy and its density slope at normal density from neutron–nucleus scattering data, going beyond the well-known Lane potential, we include consistently the second-order terms in isospin asymmetry in both the optical model potential and the symmetry energy decomposition. We find that the strength of the second-order symmetry potential U sym , 2 in asymmetric nuclear matter is significant compared to the first-order one U sym , 1 , especially at high nucleon momentum. While the U sym , 1 at normal density decreases with nucleon momentum, the U sym , 2 is found to have the opposite behavior. Moreover, we discuss effects of the U sym , 1 and U sym , 2 on determining the density dependence of the symmetry energy, and we find that the available neutron–nucleus scattering data favor a softer density dependence of the symmetry energy at normal density with a negligible contribution from the U sym , 2 .