LHCb is the heavy flavour precision experiment of the proton-proton Large Hadron Collider (LHC) at CERN. It will search for new physics in CP violation and rare decays and is ready for the start-up of the LHC. An overview of its physics program will be given, illustrated by few key examples: measurements of the CKM angle $γ$, of the CP violating phase in $ B_s \overline{B_s}$ oscillations and searches for new physics in $B^0_d \to K^*μ^+μ^-$ and in $B^0_s \to μ^+μ^-$.
The LHCb experiment at LHC is a single-arm spectrometer designed to pursue an extensive study of B physics and CP violation. In this contribution the physics which will be performed by LHCb is reviewed.
We discuss the current status and the physics prospects at the LHCb detector, the dedicated B physics detector at the LHC, due to start data taking in 2007.
LHCb is already providing leading measurements of time-dependent CP asymmetries with 1 fb$^{-1}$ of data. With the LHCb detector, and further one with the LHCb upgrade, very high-precision time-dependent CP measurements are expected to stringently test the CKM paradigm and to the search for possible small NP effects. A review of the current precision and the prospects for these time-dependent quantities with the LHCb and LHCb upgraded detectors are summarised in this paper.
High-precision measurements performed by the LHCb collaboration have opened a new era in charm physics. Several crucial measurements, particularly in spectroscopy, rare decays and CP violation, can benefit from the increased statistical power of an upgraded LHCb detector. The upgrade of LHCb detector, its software infrastructure, and the impact on charm physics are discussed in detail.
Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is poised to become a world leading experiment for charm physics, recording enormous samples with a detector tailored for flavor physics. This article presents recent charm production, CPV, and mixing studies from LHCb, including LHCb's first charm CP asymmetry measurement with 37 pb^-1 of data collected in 2010.
The status and prospects of time-integrated measurements of the CKM angle gamma at LHCb, the LHC's dedicated flavor physics experiment, are reviewed. Yields obtained from early data taking are presented and extrapolations are made to estimate what can be expected to be obtained from the 2011 data. The conclusions drawn from these extrapolations are that LHCb will produce the world's best measurement of gamma by the end of 2011 and that the long-term outlook is excellent.
The LHCb experiment is running at the Large Hadron Collider to study CP violation and rare decays in the beauty and charm sectors. The physics potential is given for five key observables sensitive to new physics in nominal conditions. The motivation and the strategy of the upgrade envisaged for 2016 is presented with the expected performance for an integrated luminosity of 50 1/fb.
The LHCb experiment is running at the Large Hadron Collider to study CP violation and rare decays in the beauty and charm sectors. The motivation and the strategy of the upgrade envisaged for the long shutdown LS2 (2018) is presented. The current results for some exemplary physics analyses are given and the expected performances foreseen for 2018 and for the LHCb Upgrade project with an integrated luminosity of 50 fb$^{-1}$ are summarized.
As first Run II data acquisition has begun, it is useful to expose the pending questions by reviewing some of the most recent results obtained with Run I data analyses. Early results of the current data taking and middle-term prospects are also shown to illustrate the efficiency of the acquisition and analysis chain.
LHCb is the dedicated B physics experiment at the LHC and is due to start data taking later this year. Its goal is to search for new physics in very rare processes and make precision measurements of CP violation in B decays. The CKM angle gamma plays an important role in flavour physics in the Standard Model. LHCb will exploit the large variety of B hadrons produced by the 14 TeV pp collisions, performing gamma measurements to the precision of a few degrees. Here, we will present a summary of the expected gamma sensitivities LHCb will reach during its first years of data taking, with contribut…
Rare decays of beauty and charm hadrons offer a rich playground to make precise tests of the Standard Model and look for New Physics at the level of quantum corrections. A review of recent LHCb results will be presented.
Studies of rare decays are an indirect probe of New Physics (NP). This document presents recent measurements of rare decays in the charm sector by the LHCb experiment. The analyses are performed with proton-proton collision data at $\sqrt{s}$ = 7 TeV recorded in 2011.
Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is poised to become a world leading experiment for charm studies, recording enormous statistics with a detector tailored for flavor physics. This article presents recent charm CPV and mixing studies from LHCb, including LHCb's first CP asymmetry measurement with 37 inverse pb of data collected in 2010. The difference of the CP asymmetries of D0 decays to the K-K+ and π-π+ final states is determined to be ΔA_{CP} = (-0.28 +/- 0.70 +/- 0.25)%. Significant updates to the materia…
Despite not being designed for it, the LHCb experiment has given world-leading contributions in kaon and hyperon physics. In this contribution I review the prospects for kaon physics at LHCb exploiting the already acquired data and the current and future Upgrade scenarios.
Rare loop-induced decays are sensitive to New Physics in many Standard Model extensions. In this paper we discuss the potential of the LHCb experiment to very rare $\mathrm{B_s} \to μ^+ μ^-$ decays, radiative penguin $\mathrm{b \to s}γ$ decays and electroweak penguin $\mathrm{b \to s\ell\ell}$ decays. The experimental strategies and the expected sensitivities are presented.
The results on rare decay processes obtained by the LHCb experiment using 1.0 fb^(-1) of pp collisions collected in 2011 at a centre-of-mass energy of sqrt(s)=7 TeV are presented. Branching fractions, angular distributions, CP and isospin asymmetries are investigated to search for new physics effects.
Following the intriguing hints of deviations from the Standard Model in rare B meson decays, searches for rare and forbidden decays of charm hadrons become a hot topic again. We present recent results on Flavour Changing Neutral Current $D^{0}\rightarrowμ^+ μ^-$, $D^0 \rightarrowμ^+μ^- π^+ π^-$, $D^{\pm}_{(s)}\rightarrow π^{\pm} μ^+μ^-$ and LFV $D^{\pm}_{(s)}\rightarrow π^{\mp}μ^{\pm}μ^{\pm}$ obtained at LHCb.
Rare decays involving leptons or photons in the final states are studied using 1.0 fb^{-1} of pp collisions at a centre-of-mass energy of sqrt{s}=7TeV collected by the LHCb experiment in 2011. We present results of measurements of branching ratios, angular distributions, and isospin asymmetries obtained using this data sample.
{Since the start of the Large Hadron Collider program, direct searches for Beyond Standard Model (BSM) particles have constrained their mass scale to limits which are now above the energy reach of the current collider. As a result, studies of indirect probes of BSM physics have gained a considerable momentum, both experimentally and theoretically. The flavour anomalies in $b$ hadron decays are now recognized as an important laboratory for the indirect detection of BSM physics. This short review presents several key analyses in this area, and some prospects with future data.
A search for the rare decay $Σ^+ \to p μ^+ μ^-$ is performed using $pp$ collision data recorded by the LHCb experiment at centre-of-mass energies $\sqrt{s} = 7$ and $8$ TeV, corresponding to an integrated luminosity of $3 fb^{-1}$. An excess of events is observed with respect to the background expectations with a signal significance of 4.0 standard deviations. No significant structure is observed in the dimuon invariant mass distribution.
Flavour-changing neutral-current processes, such as $b\to s \ell^+\ell^-$, are forbidden at tree level in the Standard Model and hence might receive comparatively large corrections from new particles. This document highlights recent measurements from LHCb on $b\to s \ell^+\ell^-$ and purely-leptonic decays, including tests of lepton flavour universality and searches for lepton flavour violation.
Rare lepton decays of the B(s), D and K mesons are sensitive probes of New Physics. In particular, the search for the decays $B^0_(s) -> μ^+ μ^-$ provides information on the presence of new (pseudo-)scalar particles. LHCb is well suited for these analyses due to its large acceptance and trigger efficiency, as well as its excellent invariant mass resolution and lepton identification capabilities. The status of these analyses with $\sim1$ fb$^{-1}$ of pp collisions collected by LHCb in 2011 at $\sqrt{s}=7$ TeV is reviewed.
The latest and improved measurements in $B^0_{(s)}\rightarrowμ^+ μ^-$ processes have been performed by LHCb using full Run 1 and Run 2 data. The measurement of the branching fraction of $B^0_{s}\rightarrowμ^+ μ^-$ is presented as the most precise single experiment measurement of such a rare process. While no significant excess is found for $B^0\rightarrowμ^+ μ^-$, an stringent upper limit is set for its braching fraction. Both results are in agreement with SM predictions and with previous results.
We review the prospects of measurements of the CKM matrix elements corresponding to the first two generations of quarks, as well as measurements of leptonic and semileptonic charm meson decays at LHCb. We review the status of searches for Lepton Non-Universality in the charm sector, and provide motivation to continue such searches.
Rare flavour changing neutral current decays are sensitive indirect probes for new effects beyond the Standard Model (SM). In the SM, these decays are forbidden at tree level and are therefore loop-suppressed. In SM extensions, new, heavy particles can significantly contribute and affect both their branching fractions as well as their angular distributions. The rare decay $B^0\to K^{*0}(\to K^+π^-)μ^+μ^-$ is of particular interest, since it gives access to many angular observables, allowing to model-independently test the operator structure of the decay. A previous analysis of the angular dist…
A review of the experimental status of purely leptonic ${B^0_{[s]}\to\ell^+\ell^-}$ decays is given and the new analysis of ${B^0_{[s]}\toμ^+μ^-}$ observables with the LHCb experiment is presented. The new results are the most precise single experiment measurements of the quantities to date and are consistent with the Standard Model. However, they also match the recent anomalies found in $b\to s\ell\ell$ transitions excellently.
We present a review of the searches for very rare decays to muonic final states performed at LHCb using 1.0 fb-1 of pp collisions at 7 TeV centre of mass energy. Flavour changing neutral current processes, such as B->mumu and B->mumumumu are highly suppressed in the Standard Model (SM). Such decays therefore allow contributions from new processes or new heavy particles to significantly modify the expected SM rates. Charged lepton flavour violating processes, such as the neutrino-less tau->mumumu decay, have vanishingly small decay rates in the SM, but can be significantly enhanced in extended …
Rare heavy flavor decays provide stringent tests of the Standard Model of particle physics and allow to test for possible new Physics scenarios. The LHCb experiment at CERN is the ideal place for these searches as it has recorded the worlds largest sample of beauty mesons. The status of the rare decay analyses with 1\invfb of $\sqrt s = 7\tev $ of $pp$--collisions collected by the LHCb experiment in 2011 is reviewed. The worlds most precise measurements of the angular structure of \BdToKstmm decays is discussed, as well as the isospin asymmetry measurement in $\decay{B}{\kaon^{(*)} \mup\mun}$ …
The LHCb experiment has the potential, during the 2010-11 run, to observe the rare decay $B^0_s\to μ^+μ^-$ or improve significantly its exclusion limits. This study will provide very sensitive probes of New Physics (NP) effects. High sensitivity to NP contributions is also achieved by measuring photon polarization by performing a time dependent analysis of $B^0_s \to ϕγ$, and by an angular study of the decay $B^0_d \to K^{*0}μ^+μ^-$. Preparations for these analyses are presented and studies shown of how existing data, for example prompt $J/ψ$ events, can be used to validate the analysis strate…
Recent results on mixing, CP violation and rare decays in charm physics from the LHCb experiment are presented. Study of ''wrong-sign'' $D^{0} \rightarrow K^+ π^-$ decays provides the highest precision measurements to date of the mixing parameters $x^{\prime 2}$ and $y^{\prime}$, and of CP violation in this decay mode. Direct and indirect CP violation in the $D^0$ system are probed to a sensitivity of around $10^{-3}$ using $D^0 \rightarrow K^+K^-$ and $D^0 \rightarrow π^+π^-$ decays and found to be consistent with zero. Searches for the rare decays $D^+_{(s)} \rightarrow π^+μ^+μ^-$, $D^+_{(s)…
Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is well equipped to take advantage of the enormous production cross-section of charm mesons in $pp$ collisions at $\sqrt{s}=7$ TeV. The measurement of the $D^0 -\bar{D}^0$ mixing parameters and the search for CP-violation in the charm sector are key physics goals of the LHCb programme. The first CP violation measurements in the charm sector, with 37 pb$^{-1}$ of data collected in 2010, are discussed. The study of $D^+ \rightarrow K^- K^+ π^+$ decays shows no indication of CP …
This report details the capabilities of LHCb and its upgrades towards the study of kaons and hyperons. The analyses performed so far are reviewed, elaborating on the prospects for some key decay channels, while proposing some new measurements in LHCb to expand its strangeness research program.
The LHCb experiment, bolstered up by the 10^12 b-hadrons to be produced yearly in its interaction region, is an excellent place to study rare B decays. Flavor-changing neutral currents are forbidden at tree level in the Standard Model. They proceed through loop diagrams and hence are indirectly sensitive to New Physics through the effect of new particles on observable quantities. In this paper, we present preparation studies of the three most promising B rare decay analyzes. These aim at the observation of the photon polarization in B_s to phi gamma, the measurement of the angular distribution…
Rare heavy flavor decays are an ideal place to search for the effects of potential new particles that modify the decay rates or the Lorentz structure of the decay vertices. The LHCb experiment, a dedicated heavy flavour experiment at the LHC at CERN. It has recorded the worlds largest sample of heavy meson and lepton decays. The status of the rare decay analyses with 1\,fb$^{-1}$ of $\sqrt s = 7\,$TeV and 1.1\,fb$^{-1}$ of $\sqrt s = 8\,$TeV of $pp$--collisions collected by the LHCb experiment in 2011 and 2012 is reviewed. The worlds most precise measurements of the angular structure of $B^0\r…
The Standard Model predicts a branching ratio for the decay mode Bs -> mu mu of (3.4 +/- 0.5)10e-9, while some SUSY models predict enhancements up to 2 orders of magnitude. It is expected that at the end of its life Tevatron will set and exclusion limit for this branching ratio of the order of 10e-8, leaving one order of magnitude to explore. The excellent vertex reconstruction, invariant mass resolution and muon identification of the LHCb detector make it well suited to observe a branching ratio in this range in the first years of running of LHC. In this article an overview of the analysis th…
A search for the Bs->mumu and Bd->mumu decays is presented using ~300 pb-1 of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The measured upper limit for the branching ratio of the Bs->mumu decay is BR(Bsmumu) < 1.3 (1.6) x 10^{-8} at 90% (95%) confidence level (CL), while in the case of the Bd->mumu decay the measured upper limit is BR(Bdmumu) < 4.2 (5.1) x 10^{-9} at 90% (95%) CL. A combination with the 2010 dataset results in BR(Bsmumu) < 1.2 (1.5) x 10^{-8} at 90% (95%) CL.
LHCb is the experiment at the Large Hadron Collider devoted to studies of new phenomena in CP violation and in rare decays. This review summarizes the status of the experiment in the imminence of the data taking, the prospects for the first measurements and highlights of its full physics program.
Rare decays are flavour changing neutral current processes that are loop-suppressed in the Standard Model (SM). New particles in SM extensions can therefore give significant contributions, modifying branching fractions and angular distributions. Consequently, rare decays are particularly sensitive probes for New Physics (NP). These proceedings summarize the latest results from the LHCb experiment on rare decays. While most results are in good agreement with SM predictions, some tensions that recently appeared in rare semileptonic $b\to s\ell^+\ell^-$ decays are also discussed.
A model that can simultaneously explain Dark Matter relic density and the apparent matter anti-matter imbalance of the universe has been recently proposed. The model requires $b$-hadron branching fractions to Dark Matter at the per mille level. The $b$-hadrons decay to a dark sector baryon, $ψ_{\rm{DS}}$, which has a mass in the region $940$ MeV/c$^{2} \leq m(ψ_{\rm{DS}}) \leq 4430$ MeV/c$^{2}$. In this paper, we discuss the sensitivity of the LHCb experiment to search for this dark baryon, covering different types of topology and giving prospects for Runs 3 and 4 of the LHC, as well as for th…
Although direct detection of new particles will be the main focus of the LHC, indirect New Physics searches are expected to provide useful complementary information. In particular, precision measurements of rare processes occurring in flavour physics are of utmost importance in constraining the structure of the New physics low energy effective Lagrangian. In this paper, few key LHCb studies, including $B_s-\bar{B}_s$ mixing and rare decays through the quark level $b\to s$ loop transition, are presented to illustrate New Physics effects at low energy.
LHCb is a dedicated detector for b and c physics at the LHC. I will present a concise review of the detector design and expected performance together with some first results on the commissioning of the different sub-systems based on cosmic data and particle beams delivered by the LHC during the summer of 2008. The experiment is ready to exploit first data expected from the LHC. An integrated luminosity of ~0.3fb-1, which should be collected during the first year of physics running, will already allow LHCb to perform a number of very significant mesurements with the potential of revealing New P…
The rare B decays Bs(d)-->μμ, B-->K*μμand Bs-->ϕγare studied using up to \sim 0.41 fb^{-1} of pp collisions at \sqrt{s} = 7 TeV collected by the \lhcb experiment in 2010 and 2011. A search for the decays Bs(d)-->μμ, is performed with 0.41 fb^{-1} . The absence of significant signal leads to BR(Bs-->μμ<1.4 x 10^{-8} and BR(Bd-->μμ<3.2 x 10^{-9} at 95% confidence level. The forward-backward asymmetry, fraction of longitudinal polarization and differential branching fraction of B-->K*μμ, as a function of dimuon invariant mass, are measured in 0.31 fb^{-1}. The ratio of branching ratios of the rad…
A search for $Σ^+ \to p μ^+ μ^-$ 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 invariant mass distribution is not confirmed, and its branching fraction central value is excluded at 95\% CL. Prospects for the future of this measurement in LHCb are also presented.
\lhcb is one of the four major experiments at the Large Hadron Collider (\lhc) at CERN. It is custom built to look for CP violation and New Physics in rare decays of heavy flavour hadrons, like the B and D systems. Rare decays that occur via loop diagrams provide a way to probe New Physics at energy scales much higher than can be probed by direct production in experiments. In this article, the \lhcb prospects for such measurements with exclusive decays of the type $B \to \Xs γ$ and $B \to X_{s} l^{+} l^{-}$ are presented.
A brief review of current results on rare kaon decays, particularly the charged and neutral K-> pi nu nubar channels, is presented along with prospects for future measurements.
LHCb is one of the four major experiments that will take data at the LHC, due to start operation in 2007. The primary aims of LHCb are to perform precision tests of CP violation and to search for new physics in b hadron decays. About 10^12 bb pairs will be produced in LHCb per 10^7 seconds (a nominal year) in pp collisions with a luminosity of 2x10^32 cm^-2 s^-1. A large, high-purity sample of b hadrons, decaying in a variety of channels, will be accumulated. LHCb will perform a detailed study of B meson mixing, precise measurements of the angles of the unitary triangle and investigations of r…
An overview of LHCb experiment is given, focusing on detector, trigger and expected physics performances. LHCb is a second generation b physics experiment design to do precise measurements of CP violation in B meson system and to study b hadron rare decays.
This article is a short and non-exhaustive summary of the prospects to find New Physics with LHCb as was presented at the HCP conference at Toronto on August 26th 2010.
A range of flavour physics observables show tensions with their corresponding Standard Model expectations: measurements of leptonic flavour-changing neutral current processes and ratios of semi-leptonic branching fractions involving different generations of leptons show deviations of the order of four standard deviations. If confirmed, either would be an intriguing sign of new physics. In this manuscript, we analyse the current experimental situation of such processes and for the first time estimate the combined impact of the future datasets of the Belle II and LHCb experiments on the present …
The coupling of the electroweak gauge bosons of the Standard Model (SM) to leptons is flavour universal. Extensions of the SM do not necessarily have this property. Rare decays of heavy flavour are suppressed in the SM and new particles may give sizeable contributions to these processes, therefore, their precise study allows for sensitive tests of lepton flavour universality. Of particular interest are rare b to sll decays that are well accessible at the LHCb experiment. Recent results from LHCb on lepton flavour universality in rare b to sll decays are discussed.
We review the first measurements of the CKM angle gamma from LHCb. These measurements have been performed with b-hadron decays dominated by b -> u and b -> c tree-level amplitudes, from which gamma can be determined without theoretical uncertainties. Precision is achieved by averaging results from B- -> Dh- (h= K,pi) decays with D -> h+h-, D -> K+pi-, and D -> K+pi-pi+pi-, and D -> K_S^0h+h-. Prospects for these and future measurements of gamma using neutral b-hadron decays are briefly discussed.
The lecture discusses both the current status of the LHC collider as well as its future running scenarios. In addition a selection of the latest physics results from ATLAS/CMS and LHCb is presented.
Belle II is an upcoming experiment at the next generation SuperKEKB e+e- collider. It will record about 50 ab-1 of data mostly at the Y(4S) resonance. The high statistics will allow precision measurements for rare decays, which can be then compared with the Standard Model predictions in order to search indirectly for new physics. We present the prospects for rare decay studies at Belle II.
We present the prospects of an angular analysis of the $Λ_b \to Λ(1520)\ell^+\ell^-$ decay. Using the expected yield in the current dataset collected at the LHCb experiment, as well as the foreseen ones after the LHCb upgrades, sensitivity studies are presented to determine the experimental precision on angular observables related to the lepton distribution and their potential to identify New Physics. The forward-backward lepton asymmetry at low dilepton invariant mass is particularly promising. NP scenarios favoured by the current anomalies in $b\to s\ell^+\ell^-$ decays can be distinguished …
