15819599
Spectral Parameters and Spectral Weights of Unstable Particles in Lattice QCD
We discuss the issues related to the spectral parameters (mass and width) of unstable particles in lattice calculations. Using a solvable model, the Lee Model, we show that the eigenvalues of the Hamiltonian, which is the spectrum measured from the Euclidean correlation functions in lattice simulations, need not be the same as the energy at which the scattering phase passes through π/2. It is in general also different from the real part of the actual pole position for the S-matrix element. These three quantities are close to one another only when the resonance is narrow. We also investigate the volume dependence of the so-called spectral weights for the energy eigenstates which can be obtained in lattice simulations. The volume dependence of this quantity helps to distinguish between one-particle and two-particle states in lattice calculations. Within the Lee model, we verify that this is indeed the case when the so-called V -particle is stable. For an unstable V -particle (resonance), this method is only applicable for narrow resonances. We argue that this conclusion should also be qualitatively correct in general theories like QCD.
6175444
TUNING THE TADPOLE IMPROVED CLOVER WILSON ACTION ON COARSE ANISOTROPIC LATTICES
Wilson quark action, with tadpole improved clover term added, is studied on coarse anisotropic lattices. The bare velocity of light parameter in this action is determined nonperturbatively using the pseudo-scalar and vector meson dispersion relations for various values of the gauge coupling β and bare quark mass parameter κ.
15925356
A heavy Higgs particle in the TeV mass range
Abstract The first simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with higher derivative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection and a nonperturbative reinterpretation of the triviality Higgs mass bound becomes necessary.
119942970
LATTICE STUDY OF SCALAR AND TENSOR GLUEBALLS
118639447
Pure gauge glueballs at finite temperature
Pure gauge glueballs at finite temperature are investigated in a large temperature range from 0:3Tc to 1:9Tc on anisotropic lattices. Optimized glueball operators are used to obtain better signals. It is found in all 20 symmetry channels that the pole masses MG of glueballs remain almost constants when the temperature approaches the critical temperature Tc from below, and start to reduce gradually with the temperature going above Tc. The glueball correlators in 0 ++ , 0 i+ , and 2 ++ channels, are also analyzed based on the Breit-Wigner ansatz by assuming a thermal width Γ to the pole mass ω0. While ω0's are insensitive to T in the whole temperature range, Γ's exhibit distinct behavior below and above Tc: They are only few percents of ω0 when T Tc and reach values of roughly Γ » ω0=2 at T … 1:9Tc.
121608815
Mean-field calculations for the three-dimensional Holstein model
The electron-phonon Holstein model is studied in three spatial dimensions. It is argued that this model can be used to account for major features of the high-Tc BaPb1-xBixO3 and BaxK1-xBiO3 systems. Mean-field calculations are performed via a path integral representation of the model. Charge-density-wave order parameters and transition temperatures are obtained.
121707872
Experimental search for the electron Electric Dipole Moment using solid state techniques
We report results of an experimental search for the permanent Electric Dipole Moment (EDM) of the electron using a solid state system. The experiment uses a paramagnetic insulator (gadolinium gallium garnet) with a large magnetic response at low temperatures. The presence of the electron EDM leads to a finite magnetization when the garnet sample is subjected to a strong electric field. The resulting magnetization can be measured using a superconducting quantum interference device (SQUID) as a magnetometer. With considerable efforts made towards controlling various sources of systematic effects, the experiment is currently free of spurious signals larger than the SQUID noise. We report the value of electron EDM of (−5.57 ± 7.98 ± 0.12) × 10−25e-cm with 120 hours of data.
125180647
On the isolated singularity of a 7-space obtained by rolling Calabi-Yau threefolds through extremal transitions
118418578
Effects of acceleration on the collision of particles in the rotating black hole spacetime
We study the collision of two geodesic particles in the accelerating and rotating black hole spacetime and probe the effects of the acceleration of black hole on the center-of-mass energy of the colliding particles and on the high-velocity collision belts. We find that the dependence of the center-of-mass energy on the acceleration in the near event-horizon collision is different from that in the near acceleration-horizon case. Moreover, the presence of the acceleration changes the shape and position of the high-velocity collision belts. Our results show that the acceleration of black holes brings about richer physics for the collision of particles.
119109295
Collision of two general geodesic particles around a Kerr-Newman black hole
We study collision of two general geodesic particles around the Kerr-Newman (KN) black hole and get the center-of-mass (CM) energy of the non-marginally and marginally bound critical particles in the direct collision and LSO collision scenarios. We find the constraint conditions that arbitrarily high CM energy can be obtained for the near-horizon collision of two general geodesic particles in the extremal KN black hole, and note that the charge decreases the value of the latitude in which arbitrarily high CM energy can occurs. We also interpret why the high-velocity collision belt centers to the equator with the increase of the charge.
119204051
Dark matter and gauge coupling unification in a supersymmetry model with vector-like matter
A bstractWIMP dark matter and gauge coupling unification are considered in an R- parity violating MSSM with vector-like matter. Dark matter is contained in an additional vector-like SU(2)L doublet which possesses a new U(1) gauge symmetry. The Higgs fields are extended to be in a $ 5\oplus \overline{5} $ representation of SU(5). The stability of dark matter is a result of gauge symmetries, and the mass of the dark matter particle is between (1.1-1.5) TeV. Dark matter has a very small cross section with nucleis, thus the model is consistent with current dark matter direct detection experiments such as Xenon100. The model also predicts new charged and colored particles to be observed at LHC.