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Register a new userNon-minimal UED confronts $B_{s}rightarrowmu^{+}mu^{-}$
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Addition of boundary localised kinetic and Yukawa terms to the action of a 5-dimensional Standard Model would non-trivially modify the Kaluza-Klein spectra and some of the interactions among the Kaluza-Klein excitations compared to the minimal version of this model, in which, these boundary terms are not present. In the minimal version of this framework known as Universal Extra Dimensional model, special assumptions are made about these unknown, beyond the cut-off contributions to restrict the number of unknown parameters of the theory to a minimal. We estimate the contribution of Kaluza-Klein modes to the branching ratios of $B_{s(d)}rightarrowmu^{+}mu^{-}$ in the framework of non-minimal Universal Extra Dimensional, at one loop level. The results have been compared to the experimental data to constrain the parameters of this model. From the measured decay branching ratio of $B_s rightarrow mu^+ mu^-$ (depending on the values of boundary localised parameters) lower limit on $R^{-1}$ can be as high as 800 GeV. We have briefly reviewed the bounds on nmUED parameter space coming from electroweak precision observables. The present analysis ($B_s rightarrow mu^+ mu^-$) has ruled out new regions of parameter space in comparison to the analysis of electroweak data. We have revisited the bound on $R^{-1}$ in Universal Extra Dimensional model, which came out to be 454 GeV. This limit on $R^{-1}$ in Universal Extra Dimensional framework is not as competitive as the limits derived from the consideration of relic density or Standard Model Higgs boson production and decay to $W^+ W^-$. Unfortunately, $B_{d}rightarrowmu^{+}mu^{-}$ decay branching ratio would not set any significant limit on $R^{-1}$ in a minimal or non-minimal Universal Extra Dimensional model.
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Kaluza-Klein (KK) parity can be violated in five-dimensional universal extra dimensional model with boundary-localized (kinetic or mass) terms (BLTs) at the fixed points of $S^1/Z_2$ orbifold. In this framework we study the resonant production of Kaluza-Klein excitations of the neutral electroweak gauge bosons at the LHC and their decay into an electron-positron pair or a muon-antimuon pair. We use the results (first time in our knowledge) given by the LHC experiment to constrain the mass range of the first KK-excitation of the electroweak gauge bosons ($B^1 textrm{and} W_3^1$). It is interesting to note that the LHC result puts an upper limit on the masses of the $n=1$ KK-leptons for positive values of BLT parameters and depending upon the mass of $ell^{+}ell^{-}$ resonance.
A search for the decay $K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}$ is performed using proton-proton collision data, corresponding to an integrated luminosity of $5.6,text{fb}^{-1}$ and collected with the LHCb experiment during 2016, 2017 and 2018 at a center-of-mass energy of $13,mathrm{TeV}$. The observed signal yield is consistent with zero, yielding an upper limit of ${cal B}(K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}) < 2.2 times 10^{-10}$ at 90% CL. The limit reduces to ${cal B}(K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}) < 2.1 times 10^{-10}$ at 90% CL once combined with the result from data taken in 2011 and 2012.
We point out that in the minimal supersymmetric standard model terms from the mixing of Higgs and Goldstone bosons which are connected to the renormalization of tan(beta) via Slavnov-Taylor identities give rise to corrections that do not vanish in the limit where the supersymmetric particles are much heavier than the Higgs bosons. These additional contributions have important phenomenological implications as they can lead to potentially large supersymmetric effects in DeltaM_d and to a significant increase of DeltaM_s relative to the standard model prediction for a light pseudoscalar Higgs A0. We calculate all the missing one-loop pieces and combine them with the known effective non-holomorphic terms to obtain improved predictions for the B_(d,s)-anti-B_(d,s) mass differences DeltaM_(d,s) and the branching ratios of B_(d,s) -> mu+mu- in the large tan(beta) regime of the minimal supersymmetric standard model with minimal flavor violation.
A search for the decay $B_{s}^0 rightarrow overline{K}{}^{*0}mu^+mu^-$ is presented using data sets corresponding to 1.0, 2.0 and 1.6 $text{fb}^{-1}$ of integrated luminosity collected during $pp$ collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations. The branching fraction of the $B_{s}^0 rightarrow overline{K}{}^{*0}mu^+mu^-$ decay is determined to be $mathcal{B}(B_{s}^0 rightarrow overline{K}{}^{*0}mu^+mu^-) = [2.9 pm 1.0~(text{stat}) pm 0.2~(text{syst}) pm 0.3~(text{norm})] times 10^{-8}$, where the first and second uncertainties are statistical and systematic, respectively. The third uncertainty is due to limited knowledge of external parameters used to normalise the branching fraction measurement.
We reemphasize that the ratio $R_{smu} equiv overline{mathcal{B}}(B_stomubarmu)/Delta M_s$ is a measure of the tension of the Standard Model (SM) with latest measurements of $overline{mathcal{B}}(B_stomubarmu)$ that does not suffer from the persistent puzzle on the $|V_{cb}|$ determinations from inclusive versus exclusive $bto cellbar u$ decays and which affects the value of the CKM element $|V_{ts}|$ that is crucial for the SM predictions of both $overline{mathcal{B}}(B_stomubarmu)$ and $Delta M_s$, but cancels out in the ratio $R_{smu}$. In our analysis we include higher order electroweak and QED corrections und adapt the latest hadronic input to find a tension of about $2sigma$ for $R_{smu}$ measurements with the SM independently of $|V_{ts}|$. We also discuss the ratio $R_{dmu}$ which could turn out, in particular in correlation with $R_{smu}$, to be useful for the search for New Physics, when the data on both ratios improves. Also $R_{dmu}$ is independent of $|V_{cb}|$ or more precisely $|V_{td}|$.
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