119447810
Note on the slope parameter of the baryonic Lambda(b) ---> Lambda(c) Isgur-Wise function
Abstract Using the framework of the Heavy Quark Effective Theory we have re-analyzed the Isgur–Wise function describing semileptonic Λ b → Λ c decays in the QCD sum rule approach. The slope parameter of the Isgur–Wise function is found to be ρ 2 = 1.35 ± 0.13 , which is consistent with an experimental measurement and a lattice calculation. To O ( 1 / m b , 1 / m c ) of the heavy quark expansion the integrated Λ b decay width is used to extract the CKM matrix element V c b for which we obtain a value of | V c b | = 0.041 ± 0.004 ± 0.001 in excellent agreement with the value of | V c b | determined from semileptonic B → D ∗ decays.
119384069
Supersymmetry for Fermion Masses
It is proposed that supersymmetry (SUSY) maybe used to understand fermion mass hierarchies. A family symmetry Z_{3L} is introduced, which is the cyclic symmetry among the three generation SU(2) doublets. SUSY breaks at a high energy scale ~ 10^{11} GeV. The electroweak energy scale ~ 100 GeV is unnaturally small. No additional global symmetry, like the R-parity, is imposed. The Yukawa couplings and R-parity violating couplings all take their natural values which are about (10^0-10^{-2}). Under the family symmetry, only the third generation charged fermions get their masses. This family symmetry is broken in the soft SUSY breaking terms which result in a hierarchical pattern of the fermion masses. It turns out that for the charged leptons, the tau mass is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the muon mass is due to the sneutrino VEVs, and the electron gains its mass due to both Z_{3L} and SUSY breaking. The large neutrino mixing are produced with neutralinos playing the partial role of right-handed neutrinos. |V_{e3}| which is for nu_e-nu_{tau} mixing is expected to be about 0.1. For the quarks, the third generation masses are from the Higgs VEVs, the second generation masses are from quantum corrections, and the down quark mass due to the sneutrino VEVs. It explains m_c/m_s, m_s/m_e, m_d>m_u and so on. Other aspects of the model are discussed.
118790054
Phenomenological aspects of R-parity violating supersymmetry with a vectorlike extra generation
Phenomenological analysis to the R-parity violating supersymmetry with a vectorlike extra generation is performed in detail. It is found that, via the trilinear couplings, the correct neutrino spectrum can be obtained. The Higgs mass rises to 125 GeV by new up-type Yukawa couplings of vectorlike quarks with no need of very heavy superpartners. Phenomena of new heavy fermions at LHC are predicted. DOI: 10.1103/PhysRevD.87.075012
119216988
LHCb $\bigtriangleup A_{CP}$ of $D$ Meson and R-Parity Violation
LHCb collaboration has recently announced a measurement of the difference of time-integrated CP asymmetries between $D\rightarrow K^+K^-$ and $D \rightarrow \pi^+\pi^-$. This result provides the evidence of large direct CP violation in $D$ meson and reveals some important implications on underlying new physics. It is shown that the direct CP violation in $D$ meson can be enhanced by R-parity violating supersymmetry, while CP violations in $K$ and $B$ mesons are suppressed by this new physics, which is in consistence with previous experiments. Constraints on the model parameters and some consequences are also discussed.
117463737
A Supersymmetric model with the gauge symmetry SU(3)(1) x SU(2)(1) x U(1)(1) x SU(3)(2) x SU(2)(2) x U(1)(2)
A supersymmetric model with two copies of the Standard Model gauge groups is constructed in the gauge mediated supersymmetry breaking scenario. The supersymmetry breaking messengers axe in a simple form. The Standard Model is obtained after first step gauge symmetry breaking. In the case of one copy of the gauge interactions being strong, a scenario of electroweak symmetry breaking is discussed, and the gauginos are generally predicted to be heavier than the sfermions.
14586429
QCD sum rule analysis for the Lambda(b)->Lambda(c) semileptonic decay
Abstract The 1 m c and 1 m b corrections to the Λ b → Λ c semileptonic decay are analyzed by QCD sum rules. Within the framework of heavy quark effective theory, the subleading baryonic Isgur-Wise function of Λ b → Λ c has been calculated. It is shown that the corrections due to the 1 m Lagrangian insertion are negligibly small. The sizable 1 m Q effect to the decay lies only in the weak current. The decay spectrum and the branching ratio are given.
120248522
Charm program at BESIII
As of May, 2011, the Beijing Spectrometer III Experiment (known as BESIII) has accumulated 2.9 fb−1 of ψ(3770) data, which is about 3.5 times the previous largest ψ(3770) data set taken by the CLEO-c Experiment. Taking advantage of the high luminosity provided by the BEPCII collider, BESIII is expected to take much more data at both 3770 MeV and higher energies. Many high precision measurements, including CKM matrix elements related to charm weak decays, decay constants fD and fDs, form factors from D semileptonic decays, Dalitz decays, searches for CP violation, and absolute decay branching fractions, will be accomplished in the near future.As of May, 2011, the Beijing Spectrometer III Experiment (known as BESIII) has accumulated 2.9 fb−1 of ψ(3770) data, which is about 3.5 times the previous largest ψ(3770) data set taken by the CLEO-c Experiment. Taking advantage of the high luminosity provided by the BEPCII collider, BESIII is expected to take much more data at both 3770 MeV and higher energies. Many high precision measurements, including CKM matrix elements related to charm weak decays, decay constants fD and fDs, form factors from D semileptonic decays, Dalitz decays, searches for CP violation, and absolute decay branching fractions, will be accomplished in the near future.
119368335
The Higgs model with a complex ghost pair
Abstract A higher derivative term is introduced in the kinetic energy of the Higgs lagrangian in the minimal Standard Model. A logically consistent and finite field theory is obtained when some excitations of the Higgs field are quantized with indefinite metric in the Hilbert space. The Landau ghost phenomenon of the ponventional triviality problem is replaced by the state vectors of a complex ghost pair at a finite mass scale with observable physical consequences. It is shown that the ghost states exhibit unusual resonance properties and correspond to a complex conjugate pair of Pauli-Villars regulator masses in the euclidean path integral formulation of the theory. An argument is given that microscopic acausality effects associated with the ghost pair remain undetectable in scattering processes with realistic wave packets, and the S -matrix should exhibit unitarity in the observable sector of the Hilbert space.
117744661
Glueballs in charmonia radiative decays
Scalar [1] and tensor [2] glueballs created in J/ψ radiative decays are studied in quenched lattice QCD. Using two anisotropic lattices to approach the continuum limit, we compute the relevant form factors responsible for the decay rates for J/ψ → γG0++ and J/ψ → γG2++ . Comparing with the existing experimental data, it is argued that f0(1710) is a favorable candidate for scalar glueball. The decay rate for J/ψ → γG2++ is found to be quite substantial. A comprehensive search in the tensor channel on BESIII is therefore suggested.
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.
118433133
Millisecond dips in the 2007–09 RXTE/PCA light curve of Sco X-1 and one possible occultation event
Serendipitous stellar occultation search is so far the only way to detect the existence of very small, very dim, remote objects in the Solar system. To date, however, there are only very few reported detections for trans-Neptunian objects (TNOs) in optical bands. In the X-ray band, with the RXTE/PCA data of Sco X-1 taken from 2007 June to 2009 October, we found one possible X-ray occultation event. We discuss the veracity and properties of this event, and suggest upper limits to the size distribution of TNOs at hectometre size and of main-belt asteroids at decametre size.