118381371
Searching for new physics with B-decay fake triple products
Abstract In pure-penguin b ¯ → s ¯ B → V 1 V 2 decays ( V 1 , 2 are vector mesons), f T / f L ≃ 1 has been observed ( f T ( f L ) is the polarization fraction of transverse (longitudinal) decays). Explanations of this unexpectedly large result have been given within the standard model (SM) and with new physics (NP). In this Letter, we show that these two explanations can be partially distinguished through the triple products (TPʼs) in these transitions. In particular, the SM predicts one of the two fake, CP-conserving TPʼs to be small ( | A T ( 2 ) | ⩽ 9 % ), while NP often gives larger values for | A T ( 2 ) | . We discuss the implications of the measurements of both fake TPʼs in B → ϕ K ⁎ – the present data prefer an SM explanation of f T / f L – and provide the SM predictions for B s 0 → ϕ ϕ .
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.
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.
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.
199680997
The Charged Lepton Mass Matrix and Non-zero $\theta_{13}$ with TeV Scale New Physics
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.
118715386
LHC limits on KK-parity non-conservation in the strong sector of universal extra-dimension models
Abstract In five-dimensional universal extra-dimensional models compactified on an S 1 / Z 2 orbifold four-dimensional kinetic terms are allowed at the two fixed points. If these terms are unequal then Kaluza–Klein (KK) parity is broken. Within such a framework we consider resonant production of the n = 1 KK-gluon at the LHC and its subsequent decay to t t ¯ , where both production and decay are KK-parity non-conserving. We use, for the first time, the exclusion data for a t t ¯ resonance obtained by the LHC experiments to limit the mass range of the lowest gluon excitation and, in a correlated fashion, of the n = 1 quark excitation of the KK-parity-violating model which are both found to be in the ballpark of 600–2000 GeV.
118555858
Enriching the exploration of the mUED model with event shape variables at the CERN LHC
Abstract We propose a new search strategy based on the event shape variables for new physics models where the separations among the masses of the particles in the spectrum are small. Collider signature of these models, characterized by low p T leptons/jets and low missing p T , are known to be difficult to look for. The conventional search strategies involving hard cuts may not work in such situations. As a case study, we have investigated the hitherto neglected jets + missing E T signature – known to be a challenging one – arising from the pair productions and decay of n = 1 KK-excitations of gluons and quarks in the minimal Universal Extra Dimension (mUED) model. Judicious use of the event shape variables enables us to reduce the Standard Model backgrounds to a negligible level. We have shown that in mUED, R − 1 up to 850 GeV can be explored or ruled out with 12 fb −1 of integrated luminosity at the 7 TeV run of the LHC. We also discuss the prospects of employing these variables for searching other beyond Standard Model physics with compressed or partially compressed spectra.
1534033
Probing two universal extra dimensions at international linear collider
Abstract We discuss collider signatures of ( 1 , 1 ) th Kaluza–Klein (KK) mode vector bosons in the framework of two universal extra dimension model, at a future e + e − collider. Production of B μ ( 1 , 1 ) and W 3 μ ( 1 , 1 ) , the ( 1 , 1 ) th KK mode vector bosons, are considered in association with a hard photon. Without caring about the decay products of B μ ( 1 , 1 ) or W 3 μ ( 1 , 1 ) , one can measure the masses of these particles just by looking at the photon energy distribution. Once produced B μ ( 1 , 1 ) ( W 3 μ ( 1 , 1 ) ) dominantly decays to a pair of jets or to a pair of top quarks. Thus we look for a pair of jets or a pair of top quarks in association with a photon. Upto the kinematic limit (with e + e − center-of-mass energies of 0.5 TeV and 1 TeV) of the collider, signals from the B μ ( 1 , 1 ) production and decay in both the above mentioned channels are greater than the 5σ fluctuation of the Standard Model background with 500 f b −1 integrated luminosity. However, the number of events from W 3 μ ( 1 , 1 ) production and decay is smaller and its detection prospect is not very good.
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.