Related papers: Phenomenology with a non-zero B_s decay width diff…
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…
The LHCb experiment has recently established a sizable width difference between the mass eigenstates of the $B_s$-meson system. This phenomenon leads to a subtle difference at the 10% level between the experimental branching ratios of $B_s$…
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…
We have just entered an era of precision measurements for $B_s$-decay observables. A characteristic feature of the $B_s$-meson system is $B^0_s$--$\bar B^0_s$ mixing, which exhibits a sizable decay width difference. The latter feature leads…
The Standard Model predicts a large width difference in the $B_s$ system. New physics can contribute significantly to the {\it mass} difference. If this contribution is CP violating, this will always result in a reduction of the {\it width}…
A width difference of the order of 20\% has previously been predicted for the two mass eigenstates of the $B_s$ meson. The dominant contributor to the width difference is the $b\rightarrow c\bar c s$ transition, with final states common to…
We update the Standard-Model predictions for several quantities related to $B_s - \bar B_s$ and $B_d - \bar B_d$ mixing. The mass and width differences in the $B_s$ system read $ \Delta M_s^{\rm SM} = (17.3 \pm 2.6) ps^{-1}$ and $\Delta…
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 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…
The measurement of $B_s$-meson branching fractions is a fundamental tool to probe physics beyond the Standard Model. Every measurement of untagged time-integrated $B_s$-meson branching fractions is model-dependent due to the time dependence…
I review the status of the rare decays B_s --> mu+mu- and B_d --> mu+mu-. The latest Standard Model predictions for the corresponding branching ratios are discussed. An overview of additional observables that are accessible in the B_s -->…
A new way of probing new physics in the $B$ meson system is provided. We define double ratios for the observables of $B_{d,s}$-$\Bbar_{d,s}$ mixings and $B_{d,s}\to\mu^+\mu^-$ decays, and find simple relations between the observables. By…
Measurements of the effective lifetimes of $B_s$-meson decays, which only require untagged rate analyses, allow us to probe the width difference $\Delta\Gamma_s$ and the CP-violating phase $\phi_s$ of $B^0_s$-$\bar B^0_s$ mixing. We point…
The decay $B^0_s\to\mu^+\mu^-$ is a key probe for the search of physics beyond the Standard Model. While the current measurements of the corresponding branching ratio agree with the Standard Model within the uncertainties, significant…
We estimate the decay width difference $\Delta Gamma_d / \Gamma_d$ in the $B_d$ system including $1/m_b$ contributions and next-to-leading order QCD corrections, and find it to be around 0.3%. We explicitly show that the time measurements…
Heavy meson pairs produced in the decays of heavy quarkonium resonances at e+ e- machines (beauty and tau-charm factories) have the useful property that the two mesons are in the CP-correlated states. By tagging one of the mesons as a CP…
The presence of a sizeable CP-violating phase in B_s^0-B_s^0-bar mixing would be an unambiguous signal of physics beyond the Standard Model. We analyse various possibilities to detect such a new phase considering both tagged and untagged…
It is very well known that the rare electroweak processes could be very sensitive to the physics beyond the Standard Model. These processes are described with quantum loop diagrams containing also heavy particles. We show that the…
Transitions of the type $b \to s l^+ l^-$ are flavour changing neutral current processes where new physics can enter in competing loop diagrams with respect to the Standard Model contributions. In these decays several observables sensitive…
Many topics are discussed in b physics including lifetimes, decay mechanisms, determinations of the CKM matrix elements |V_{cb}| and |V_{ub}|, facilities for b quark studies, neutral $B$ meson mixing, rare b decays, hadronic decays and CP…