118592122
Probing light pseudoscalar, axial vector states through $\eta_{b} \to\tau^{+}\tau^{-}$
In this paper, we explore the decay ${\ensuremath{\eta}}_{b}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ as a probe for a light pseudoscalar or a light axial vector state. We estimate the standard model branching ratio for this decay to be $\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$. We show that considerably larger branching ratios, up to the present experimental limit of $\ensuremath{\sim}8%$, are possible in models with a light pseudoscalar or a light axial vector state. As we do not include possible mixing effects between the light pseudoscalar and the ${\ensuremath{\eta}}_{b}$, our results should be reliable when the pseudoscalar mass is away from the ${\ensuremath{\eta}}_{b}$ mass.
118496504
Model independent predictions for rare top decays with weak coupling
Measurements at B factories have provided important constraints on new physics in several rare processes involving the B meson. New physics, if present in the b quark sector may also affect the top sector. In an effective Lagrangian approach, we write down operators, where effects in the bottom and the top sector are related. Assuming the couplings of the operators to be of the same size as the weak coupling g of the standard model and taking into account constraints on new physics from the bottom sector as well as top branching ratios, we make predictions for the rare top decays t{yields}cV, where V={gamma}, Z. We find branching fractions for these decays within possible reach of the LHC. Predictions are also made for t{yields}sW.
118720377
Explaining the $B \to K^\ast \mu^+ \mu^-$ data with scalar interactions
Recent LHCb results on the decay $B \to K^\ast \mu^+ \mu^-$ show significant deviations from the SM estimates in some of the angular correlations. In this paper we study the possibility of explaining these deviations using new scalar interactions. We show that new dimension-6 four-quark operators of scalar and pseudo-scalar type can successfully account for the discrepancies even after being consistent with other experimental measurements. We also briefly discuss possible extensions of the Standard Model where these operators can be generated.
119451753
Extracting alpha from B0(d) --> K0 anti-K0 Decays
We propose a new method for obtaining the CP phase alpha, based on measurements of B0(d) --> K0 anti-K0, along with theoretical input. Due to the similarities of QCD factorization (QCDf) and perturbative QCD (pQCD), this input is basically the same for each of these models. Although the theoretical error is large at present, many of the contributing quantities will be better known in the future, leading to a smaller error. One outstanding question is the extent to which the precision on quark masses, especially m_c/m_b, can be improved. If one assumes that new physics is not present, the method can be used to predict the values of CP asymmetries in B0(d) --> K0 anti-K0: 0.02 <= A_{dir}^2 + A_{mix}^2 <= 0.125. A result outside this range would signal the existence of long-distance effects beyond those included in models of nonleptonic decays based on factorization (such as QCDf and pQCD), or the presence of new physics.
119063690
$B \to VV$ Decays - Polarization and Triple Products
We discuss how triple product asymmetries can be used to discover and constrain new physics in $B \to VV$ decays.
15656176
Understanding the nature of Ds(2317) and Ds(2460) through nonleptonic B decays
We consider the nonleptonic B decays B→D(∗)Ds(2317) and B→D(∗)Ds(2460), involving the newly discovered Ds(2317) and the Ds(2460) states. We find that experiments indicate disagreement with model calculations of their properties and/or breakdown of the factorization assumption for these decays. We point out that decays involving Bs mesons where the Ds resonances can be produced via the weak decay of the b quark can provide further information about the nature of these newly discovered states. We also propose a model to calculate the two body nonleptonic decays B→D(∗)Ds(2317)(Ds(2460)), if the Ds(2317) and Ds(2460) are interpreted as DK and D∗K molecules.
12391468
IDENTIFYING THE CONTRIBUTIONS OF UNIVERSAL EXTRA DIMENSIONS IN THE HIGGS SECTOR AT LINEAR e+e- COLLIDERS
We study the dilepton–dijet signal in the dominant Higgs production channel at a linear e+e- collider. We estimate the effects of universal extra dimension (UED) by a simple analysis of the cross-sections. The heavy Kaluza–Klein excitations of the Standard Model fields in UED can significantly alter the decay properties of the Higgs boson to loop-driven final states. We show that by taking a simple ratio between cross-sections of two different final states this difference can be very easily highlighted.
125209638
What does the mu(nu) oscillate into
14433498
SUSY resonances from UHE neutralinos in neutrino telescopes and in the sky
In the Top-down scenarios, the decay of super-heavy particles (m ∼ 10 12−16 GeV), situated in dark-matter halos not very far from our Galaxy, can explain the ultra-high-energy (UHE) cosmic-ray spectrum beyond the Griesen-Zatasepin-Kuzmin cut-off. In case the dynamics of this decay is governed by the minimal supersymmetric standard model, a major component of the UHE cosmic-ray flux at PeV-EeV energies could be given by the lightest neutralino � 0 , that is the lightest stable supersymmetric particle. Then, the signal of UHE � 0 ’s on earth might emerge over the interactions of a comparable neutrino component. We compute the event rates for the resonant production of right selectrons (˜eR) and right squarks (˜qR) in mSUGRA, when UHE neutralinos of energy E� > 10 5 GeV scatter off electrons and quarks in an earth-based detector like IceCube. When the resonant channel dominates in the total � 0 e,� 0 q scattering cross section, the only model parameters affecting the corresponding visible signal rates turn out to be the physical masses of the resonant right-scalar and of the lightest neutralino. We compare the expected number of supersymmetric events with the rates corresponding to the expected
2177649
Prospects of squark and slepton searches at a $\gamma \gamma$ collider
Abstract We examine the prospects of detecting sfermions at a gamma–gamma collider. Once produced, a slepton can decay into a pair of quarks (jets) through R -parity violating interactions. Similarly, a squark may decay into a lepton–quark pair. Analyzing the corresponding Standard Model backgrounds, namely 4-jet and dilepton plus dijet final states respectively, we show that the sfermion can be detected almost right upto the kinematic limit and its mass determined to a fair degree of accuracy. Similar statements also hold for nonsupersymmetric leptoquarks and diquarks.
119178079
Universal Extra-Dimensional Models with Boundary Localized Kinetic Terms: Probing at the LHC
In universal extra-dimensional models a conserved $Z_2$ parity ensures the stability of the lightest Kaluza-Klein particle, a potential dark-matter candidate. We show here that boundary-localized kinetic terms, in general, do not preserve this symmetry. We examine the single production of a Kaluza-Klein excitation of the photon and its decay to zero-mode fermion-antifermion pairs in the presence of such terms. We explore how experiments at the Large Hadron Collider at CERN can help constrain the boundary-localized kinetic terms for different choices of the compactification radius.