119429343
Comparative analysis of non-perturbative effects in B ---> X(u)l anti-nu(l) decays
In order to extract the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}| from B -> X_u l anti-nu_l decays, the overwhelming background from B -> X_c l anti-nu_l decays must be reduced by appropriate acceptance cuts. We study the non-perturbative effects due to the motion of the b quark inside the B meson on the phenomenologically relevant decay distributions of B -> X_u l anti-nu_l in the presence of such cuts in a comparative analysis based on shape functions and the parton model in the light-cone limit. Comparisons with recent data from the CLEO, BABAR, and BELLE collaborations favor the shape-function approach.
119670186
Padé Expansion and the Renormalization of Nucleon–Nucleon Scattering
The importance of imposing physical boundary conditions on the T-matrix to remove the nonperturbative renormalization prescription dependence is stressed and demonstrated in two diagonal channels 1P1 and 1D2, with the help of Pade expansion.
15356070
Can QFT be UV finite as well as effective
A new attempt is demonstrated that QFTs can be UV finite if they are viewed as the low energy effective theories of a fundamental underlying theory (complete and well-defined in all respects) according to the modern standard point of view. This approach is much simpler in principle and in technology comparing to any known renormalization program. Some subtle and difficult issues can be easily resolved. The importance of the procedure for defining the ambiguities is fully appreciated in the new approach. Some simple but important nonperturbative examples are discussed to show the power and plausibility of the new approach.
120520076
Soliton mass and discrete coupling constants in the quantized sine-Gordon model
The soliton mass in the quantized sine-Gordon model over the whole range of the coupling constant (g2 from 0 to 8 pi ) is evaluated by means of the Gaussian effective potential method. The analytical expression with numerical results is presented. The authors find that the coupling constant g can only take discrete values. A new kind of soliton linking g Phi =0 to g Phi = pi emerges at a set of special coupling constants g.
14239579
Confinement of Higgs bosons from hidden symmetry and convexity
In the full effective potential (EFP) approach, we find that spontaneous symmetry breaking (SSB) can, with the convexity of the full EFP, lead to the prediction of the IR confinement of Higgs particles, adding difficulty to the experimental identification of Higgs particles. The short distance behaviors remain intact. The whole presentation is given in the understanding that any QFT becomes UV well defined in a more complete underyling theory according to a recently proposed strategy.
13049479
A new kind of constraints on renormalization schemes
We derive a new kind of physical constraints on the subtraction schemes for theories with massive particles in addition to the Ward identities for gauge symmetries. The momentum subtraction scheme fails this criterion. The decoupling of heavy fields is discussed in the context of Callan-Symanzik equations where all schemes (including MOM) lead to the same pattern of decoupling with inevitable discontinuities in beta function across heavy field thresholds. PACS number(s): 11.10.Gh; 11.10.Hi; 12.39.Hg
15804712
Probing R-violating top quark decays at the NLC
Abstract We examine the possibility of observing exotic top quark decays via R -parity violating SUSY interactions in e + e − collisions at s =500  GeV. We present cross-sections for t t production followed by the subsequent decay of either the t or t via the R -parity violating interaction while the other undergoes the SM decay. We discuss kinematic cuts that allow the exotic SUSY decays to be detected over standard model backgrounds. Discovery limits for R -parity violating couplings in the top sector are presented assuming an integrated luminosity of 100 fb −1 .
123028444
Study on Spin Precession of Polarized Slow Positrons in Solids
We have investigated spin precession mechanisms of polarized slow positrons in materials caused by multiple Coulomb scatterings, Bhabha scatterings and bremsstrahlungs. It is found that the degree of depolarization is strongly dependent on the atomic number of materials, and the depolarizations caused by the Bhabha scatterings and the bremsstrahlungs are negligible compared with those caused by multiple Coulomb scatterings. By incorporating the theoretical formulations of spin precession due to the three processes mentioned above into a Monte-Carlo simulation program, we can successfully describe depolarizations of polarized slow-positron beams in materials, i.e. a target, an absorber, and a moderator which are utilized for slow-positron production facilities. The magnitudes of the polarizations thus estimated are in good agreement with experimental measurements.
117034934
Asymmetric Sneutrino Dark Matter in the NMSSM with Minimal Inverse Seesaw
We dynamically realize the supersymmetric inverse seesaw mechanism in the next to the minimal supersymmetic standard model (NMSSM) in a minimal form. The crucial observation is that the inclusion of a dimension-five operator ¯
56228854
Constraints of dark matter direct detection experiments on the MSSM and implications for LHC Higgs searches
Assuming the lightest neutralino solely composes the cosmic dark matter, we examine the constraints of the CDMS-II and XENON100 dark matter direct searches on the parameter space of the MSSM Higgs sector. We find that the current CDMS-II/XENON100 limits can exclude some of the parameter space which survive the constraints from the dark matter relic density and various collider experiments. We also find that in the currently allowed parameter space, the charged Higgs boson is hardly accessible at the LHC for an integrated luminosity of 30 fb−1, while the neutral non-SM Higgs bosons (H,A) may be accessible in some allowed region characterized by a large μ. The future XENON100 (6000 kg-days exposure) will significantly tighten the parameter space in case of nonobservation of dark matter, further shrinking the likelihood of discovering the non-SM Higgs bosons at the LHC. PACS numbers: 14.80.Da,14.80.Ly
122580738
B meson dileptonic decays in the next-to-minimal supersymmetric model with a light CP-odd Higgs boson
In the next-to-minimal supersymmetric model (NMSSM) a light CP-odd Higgs boson is so far allowed by current experiments, which, together with a large tan beta, may greatly enhance the rare dileptonic decays B -> X(s)l(+)l(-) and B(s)-> l(+)l(-)gamma. We examine these decays paying special attention to the new operator allowed by the light CP-odd Higgs boson. We find that in the parameter space allowed by current experiments like CERN LEP II and b -> s gamma, the branching ratios of these rare decays can be greatly enhanced, and thus the existing experimental data on B -> X(s)mu(+)mu(-) can further stringently constrain the parameter space (especially the region with a superlight CP-odd Higgs boson and large tan beta). In the surviving parameter space we give the predictions for other dileptonic decay branching ratios and also show the results for the forward-backward asymmetry.