相关论文: Constraints on the new particle in $\Sigma^+\to p\…

If the HyperCP three events for the decay of $\Sigma^+\to p\mu^+\mu^-$ are explained by a new pseudoscalar (axial-vector) boson $X_{P(A)}$ with a mass of 214.3 MeV, we study the constraints on the couplings between $X_{P(A)}$ and fermions…

The HyperCP collaboration has recently reported the observation of three events for the decay \Sigma^+ \to p mu^+ mu^- with an invariant mass m_{\mu^+\mu^-} for a muon and an anti-muon pair of \sim 214 MeV. They suggest that a new particle…

We report the first evidence for the decay Sigma+ -> p mu+ mu- from data taken by the HyperCP experiment(E871) at Fermilab. Based on three observed events, the branching ratio is B(Sigma+ -> p,mu+,mu-) = [8.6 +6.6,-5.4(stat) +/-5.5(syst)] x…

We consider the existence of the state X^0 (214 MeV) in Sigma^+ -> p mu^+ mu^- decay found by the HyperCP collaboration. We assume that a fundamental spin zero boson X^0 coupled to quarks leads to flavor changing s -> d X^0 process. We…

The HyperCP collaboration observed three events for the decay Sigma to p mu+ mu-. They suggested that new physics may be required to understand the implied decay rate and the observed dimuon invariant mass distribution. Motivated by this…

The HyperCP collaboration has observed three events for the decay Sigma^+ -> p mu^+ mu^- which may be interpreted as a new particle of mass 214.3 MeV. However, existing data from kaon and B-meson decays severely constrain this…

To explain the anomalously large decay rate of $\Sigma^+\to p+\mu^+\mu^-$, it was proposed that a new mechanism where a light CP-odd pseudoscalar boson of $m_{A_1^0}=214.3$ MeV makes a crucial contribution. Later, some authors have studied…

The rare decay $B^0_s \to \mu^+\mu^-$ plays a key role for the testing of the Standard Model. It is pointed out that the sizable decay width difference $\Delta\Gamma_s$ of the $B_s$-meson system affects this channel in a subtle way. As a…

Leptonic rare decays of $B^0_{s,d}$ mesons offer a powerful tool to search for physics beyond the Standard Model. The $B^0_{s}\to\mu^+\mu^-$ decay has been observed at the Large Hadron Collider and the first measurement of the effective…

We have recently seen new upper bounds for $B^0_s\to \mu^+\mu^-$, a key decay to search for physics beyond the Standard Model. Furthermore a non-vanishing decay width difference $\Delta\Gamma_s$ of the $B_s$ system has been measured. We…

We perform a model independent analysis of new physics in $B^*_s \rightarrow \mu^+ \mu^-$ decay. We intend to identify new physics operator(s) which can provide large enhancement in the branching ratio of $B^*_s \rightarrow \mu^+ \mu^-$…

Decays of the kind $B^0_{s,d}\to\ell^+\ell^-$ belong to the most favourable processes for probing the flavour structure of the Standard Model, with outstanding sensitivity to new (pseudo)-scalar contributions. While the branching ratio of…

We further discuss possible sgoldstino interpretation of the observation, reported by the HyperCP collaboration, of three \Sigma^+\to p\mu^+\mu^- decay events with dimuon invariant mass 214.3 MeV within detector resolution. With sgoldstino…

The rare decays $B_{s(d)} \to \mu^+\mu^-$ play a key role for the testing of the Standard Model. An overview of the most recent theoretical predictions of the corresponding branching ratios is given, emphasizing that the sizable decay width…

We explore supersymmetric contributions to the decay $K_S^0\rightarrow\mu^+\mu^-$, in light of current experimental data. The Standard Model (SM) predicts $\mathcal{B}(K_S^0\rightarrow\mu^+\mu^-)\approx5\times 10^{-12}$. We find that…

The B_s to mu+ mu- decay plays an outstanding role in tests of the Standard Model and physics beyond it. The LHCb collaboration has recently reported the first evidence for this decay at the 3.5 sigma level, with a branching ratio in the…

A search for $\Sigma^+ \to p \mu^+ \mu^-$ decays with LHCb Run 1 data is presented, yielding an evidence for this decay and a measurement of a branching fraction compatible with the Standard Model. The HyperCP anomaly in the dimuon…

We analyze the inclusive $b(c) \to s(u) \mu^+ \mu^-$ and the exclusive $B(D^+) \to K(\pi^+) \mu^+ \mu^-$ flavour changing neutral current decays in the light of HyperCP boson $X^0$ of mass 214 MeV recently observed in the hyperon decay…

\noindent A search for the decays $B^0_{s}\rightarrow \mu^+ \mu^- \mu^+ \mu^-$ and $B^0 \rightarrow \mu^+ \mu^- \mu^+ \mu^-$ is performed using data, corresponding to an integrated luminosity of 1.0\ensuremath{\{\,fb}^{-1}}\xspace,…

A search for a long-lived scalar particle $\chi$ is performed, looking for the decay ${B^+ \to K^+ \chi}$ with ${\chi \to \mu^+\mu^-}$ in $pp$ collision data corresponding to an integrated luminosity of $3\, {\rm fb}^{-1}$, collected by the…