117055056
A study of CP violation in K and B meson decays
117495229
Light gluino and the running of alpha(s)
A gluino in the mass range 12--16 GeV combined with a light (2--5.5 GeV) bottom squark, as has been proposed recently to explain an excess of b quark hadroproduction, would affect the momentum-scale dependence (``running'') of the strong coupling constant alpha_s in such a way as to raise its value at M_Z by about 0.014 +/- 0.001. If one combines sources of uncertainty at low (m_b) and high (M_Z) mass scales, one can only distinguish such an effect at slightly more than the 2 sigma level. Prospects for improvement in this situation, which include better lattice QCD simulations and better measurements at M_Z, are discussed.
119207675
Phenomenology of large mixing for the CP-even neutral scalars of the Higgs triplet model
The Higgs triplet model contains two CP-even neutral scalar eigenstates, each having components from an isospin doublet and an isospin triplet scalar field. The mixing angle can be maximal if the masses of the scalar eigenstates are close to degeneracy. We quantify the dependence of the mixing angle on the mass splitting and on the vacuum expectation value of the neutral triplet scalar. We determine the parameter space for maximal mixing, and study the observability of both CP-even Higgs bosons at the CERN LHC.
119354846
Final state phases in B ---> D pi, d* pi, and D(rho) decays
The final-state phases in $\bar{B} \to D \pi, D^* \pi$, and $D \rho$ decays appear to follow a pattern similar to those in $D \to \bar{K} \pi$, $\bar{K}^* \pi$, and $\bar{K} \rho$ decays. Each set of processes is characterized by three charge states but only two independent amplitudes, so the amplitudes form triangles in the complex plane. For the first two sets the triangles appear to have non-zero area, while for the $D \rho$ or $\bar{K} \rho$ decays the areas of the triangles are consistent with zero. Following an earlier discussion of this behavior for $D$ decays, a similar analysis is performed for B decays, and the relative phases and magnitudes of contributing amplitudes are determined. The significance of recent results on $\ob \to D^{(*)0} \bar{K}^{(*)0}$ is noted. Open theoretical and experimental questions are indicated.
15356463
Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons
Global fits to charmless B→PP decays in the framework of flavor SU(3) symmetry are updated and improved without reference to the sin 2β measured from the charmonium decay modes. Fit results directly constrain the (,) vertex of the unitarity triangle, and are used to predict the branching ratios and CP asymmetries of all decay modes, including those of the Bs system. Different schemes of SU(3) breaking in decay amplitude sizes are analyzed. The major breaking effect between strangeness-conserving and strangeness-changing decays can be accounted for by including a ratio of decay constants in tree and color-suppressed amplitudes. The possibility of having a new physics contribution to Kπ decays is also examined from the data fitting point of view.
119209992
Testing the custodial symmetry in the Higgs sector of the Georgi-Machacek model
A bstractWe study how the custodial symmetry in the Higgs sector of the Georgi-Machacek (GM) model can be tested at the LHC. As the minimal extension of the Higgs triplet model, in which tiny neutrino masses are generated via the Type-II Seesaw Mechanism, the GM model keeps the electroweak ρ parameter at unity at tree level. In the GM model, there are 5-plet (H5), 3-plet (H3) and singlet (H1) Higgs bosons under the classification of the custodial SU(2)V symmetry, in addition to the standard model-like Higgs boson (h). These new Higgs bosons have the following characteristic features at the tree level: (1) the masses of the Higgs bosons belonging to the same SU(2)V multiplet are degenerate; and (2) H5 and H1 couple to the electroweak gauge bosons but not SM quarks, whereas H3 couples to the quarks but not the gauge bosons. We find that the H5 production from the weak vector boson fusion process and the Drell-Yan process associated with H3 are useful in testing the custodial symmetry of the Higgs sector at the LHC. In addition, these processes can also be used to discriminate from other models that contain singly-charged Higgs bosons and extra neutral Higgs bosons. We also investigate a possible enhancement in the h → γγ as well as h → Zγ decays.
54957266
Constraining the detailed balance condition in Hořava gravity with cosmic accelerating expansion
In 2009 Hořava proposed a power-counting renormalizable quantum gravity theory. Afterwards a term in the action that softly violates the detailed balance condition has been considered with the attempt of obtaining a more realistic theory in its IR-limit. This term is proportional to ωR(3), where ω is a constant parameter and R(3) is the spatial Ricci scalar. In this paper we derive constraints on this IR-modified Hořava theory using the late-time cosmic accelerating expansion observations. We obtain a lower bound of |ω| that is nontrivial and depends on ΛW, the cosmological constant of the three dimensional spatial action in the Hořava gravity. We find that to preserve the detailed balance condition, one needs to fine-tune ΛW such that −2.29 × 10−4 < (c2ΛW)/(H20ΩDE)−2 < 0, where H0 and ΩDE are the Hubble parameter and dark energy density fraction in the present epoch, respectively. On the other hand, if we do not insist on the detailed balance condition, then the valid region for ΛW is much relaxed to −0.39 < (c2ΛW)/(H20ΩDE)−2 < 0.12. We find that although the detailed balance condition cannot be ruled out, it is strongly disfavored.
119227092
Dark matter detection with polarized detectors
Abstract We consider the prospects to use polarized dark-matter detectors to discriminate between various dark-matter models. If WIMPs are fermions and participate in parity-violating interactions with ordinary matter, then the recoil-direction and recoil-energy distributions of nuclei in detectors will depend on the orientation of the initial nuclear spin with respect to the velocity of the detector through the Galactic halo. If, however, WIMPS are scalars, the only possible polarization-dependent interactions are extremely velocity-suppressed and, therefore, unobservable. Since the amplitude of this polarization modulation is fixed by the detector speed through the halo, in units of the speed of light, exposures several times larger than those of current experiments will be required to be probe this effect.