15319479
Planck-Scale Phenomenology and Symmetry in Randers--Finsler Spaces
Lorentz Violation is a common feature of Planck-scale phenomenology. We show that the symmetry of Randers spaces deduces a modified dispersion relation, which takes the quantum gravity effects into account. The counterparts of the Lorentz transformation in the Einstein’s Special Relativity are presented explicitly. The coordinate transformations are unitary and form a group. Generators and algebra satisfied by them are different from usual Lorentz ones. The Randersian line element as well as speed of light is invariant under the transformations. In particular, there is another invariant speed which is related with Planck scale and the mass of moving particle. This is the feature of Planck scale phenomenology. Thus, the Randers spaces is a suitable framework to discuss the Planck scale effects. PACS numbers: 03.30.+p, 04.60.-m, 11.30.Cp changz@mail.ihep.ac.cn lixin@mail.ihep.ac.cn
118441255
OPERA SUPERLUMINAL NEUTRINOS AND KINEMATICS IN FINSLER SPACETIME
The OPERA collaboration recently reported that the muon neutrinos could be superluminal. More recently, Cohen and Glashow pointed that such superluminal neutrinos would be suppressed since they lose their energies rapidly via bremsstrahlung. Here, we propose that the Finslerian nature of the space time could account for the superluminal phenomena of particles. The Finsler spacetime permits the existence of the superluminal behavior of particles while the causality still holds. A new dispersion relation is obtained in a class of Finsler spacetimes. It is shown that the superluminal speed is linearly dependent on the energy per unit mass of the particle. We find that such a superluminal speed formula is consistent with the data of the OPERA, MINOS and Fermilab-1979 neutrino experiments as well as the observations on the neutrinos from the SN1987A.
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.
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.
118130623
Quantum resonance scheme to measure the gravitational constant G
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.
53695340
Exclusive radiative B-meson decays within the aligned two-Higgs-doublet model
A bstractIn the aligned two-Higgs-doublet model, the alignment of Yukawa matrices in flavour space guarantees the absence of tree-level flavour-changing neutral currents, while allowing at the same time for new sources of CP violation, implying potentially large effects in many low-energy processes. In this work we study the constraints from exclusive radiative B → V γ decays, where V denotes a light vector meson. The current experimental data on the CP-averaged branching ratios and the direct CP and isospin asymmetries are analyzed. It is found that, while the branching ratios and direct CP asymmetries do not constrain the parameter space much further compared to the inclusive B → Xs,d γ decays, complementary constraints can be obtained from the isospin asymmetries Δ(K*γ) and Δ(ργ). In addition, correlations between the various observables in exclusive B → V γ and inclusive B → Xs,d γ decays are investigated in detail, and predictions are made for several so far unmeasured observables.
1941882
Reexamining charmless B ---> PV decays in QCD factorization approach
Using the QCD factorization approach, we reexamine the two-body hadronic charmless $B$-meson decays to final states involving a pseudoscalar~($P$) and a vector~($V$) meson, with inclusion of the penguin contractions of spectator-scattering amplitudes induced by the $b\to D g^\ast g^\ast$~(where $D=d$ or $s$, and $g^\ast$ denotes an off-shell gluon) transitions, which are of order $\alpha_s^2$. Their impacts on the CP-averaged branching ratios and CP-violating asymmetries are examined. We find that these higher order penguin contraction contributions have significant impacts on some specific decay modes. Since $B\to \pi K^{\ast}$, $K \rho$ decays involve the same electro-weak physics as $B\to \pi K$ puzzles, we present a detailed analysis of these decays and find that the five R-ratios for $B\to \pi K^{\ast}$, $K \rho$ system are in agreement with experimental data except for $R(\pi K^*)$. Generally, these new contributions are found to be important for penguin-dominated $B\to PV$ decays.
119233306
Single-nucleon potential decomposition of the nuclear symmetry energy
The nuclear symmetry energy $E_{sym}(\rho)$ and its density slope $L(\rho)$ can be decomposed analytically in terms of the single-nucleon potential in isospin asymmetric nuclear matter. Using three popular nuclear effective interaction models which have been extensively used in nuclear structure and reaction studies, namely, the isospin and momentum dependent MDI interaction model, the Skyrme Hartree-Fock approach and the Gogny Hartree-Fock approach, we analyze the contribution of different terms in the single-nucleon potential to the $E_{sym}(\rho)$ and $L(\rho)$. Our results show that the observed different density behaviors of $E_{sym}(\rho)$ for different interactions are essentially due to the variation of the symmetry potential $U_{sym,1}(\rho,k)$. Furthermore, we find that the contribution of the second-order symmetry potential $U_{sym,2}(\rho,k)$ to the $L(\rho)$ generally cannot be neglected. Moreover, our results demonstrate that the magnitude of the $U_{sym,2}(\rho,k)$ is generally comparable with that of $U_{sym,1}(\rho,k)$, indicating the second-order symmetry potential $U_{sym,2}(\rho,k)$ may have significant corrections to the widely used Lane approximation to the single-nucleon potential in extremely neutron(proton)-rich nuclear matter.
118376307
Search for GeV Gamma‐Ray Bursts with the ARGO‐YBJ Detector in Scaler Mode
The ARGO‐YBJ experiment is a full coverage array made of Resistive Plate Chambers (RPCs) operated in streamer mode to detect the extensive array showers (EASs). With large field of view (>2sr) and high duty cycle (>90%), the ARGO‐YBJ detector is the right ground‐based apparatus to detect VHE GRBs, while the high altitude (4300 m a.s.l) and scaler working mode enable it to detect GRBs in the GeV region as high energy follow‐up observation of satellites such as SWIFT. If a GRB signal is detected, the four scaler channels, which correspond to different energy thresholds, can provide further information on the energy spectrum and its cut‐off. More than 40 SWIFT GRBs were in ARGO‐YBJ field of view, no significant excess was detected till now.
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