LHCb experiment at CERN has recently reported a set of measurements on lepton flavour universality in b to s transitions showing a departure from the Standard Model predictions. I will review the main ideas recently put forward to make sense out of these intriguing hints. Focusing on the new physics explanation, I will discuss the correlated signals expected in other low- and high- energy...
Rare b-hadron decays, which proceed via flavour changing neutral current (FCNC) transitions, provide a powerful test of the Standard Model of particle physics. I will present a short review of recent results on rare FCNC transitions from the LHC experiments, and will discuss some interesting tensions that have started to appear between experimental measurements and the Standard Model...
Radiative and electroweak penguin B decays proceed through one loop diagrams at the lowest order. Since new particles beyond the Standard Model can enter in the loop, these processes are very sensitive to new physics. We will report on the recent results on inclusive and exclusive modes of radiative and electroweak penguin B meson decays, including $B \to X_s \gamma$, $K^* l^+ l^-$ and $h \nu...
Rare decays are flavour changing neutral current processes that allow sensitive searches for phenomena beyond the Standard Model (SM).
In the SM, rare decays are loop-suppressed and new particles in SM extensions can give significant contributions.
The very rare decay Bs->mumu is in addition helicity suppressed and constitutes a powerful probe for new (pseudo) scalar particles.
Of particular...
Measurements of $b \to s$ transitions in semi-leptonic, leptonic and radiative decays of the the $B$ meson has come of age with several collider and flavour-factory experiments focusing on these over the past years. While the inclusive and leptonic channels have been computed to relatively high precision, the exclusive decays are fraught with uncertainties stemming from both non-factorizable...
Rare b->s(gamma,ll) decays are flavour changing neutral current processes that are forbidden at the lowest perturbative order in the Standard Model (SM).
As a consequence, new particles in SM extensions can significantly affect the branching fractions of these decays and give rise to new sources of CP-violation.
The LHCb experiment is ideally suited for the analysis of rare decays due to the...
Lepton Flavor (Universality) Violation in B Meson Decays
Even though the LHC searches so far did not unveil the new physics particles, the B-physics experiments at LHCb, BaBar and Belle hint towards deviations from Lepton Flavor Universality in both the tree-level and loop-induced B meson semileptonic decays. I will briefly review the models that can address these puzzles, propose one new...
Phenomena beyond the standard model (SM) can manifest themself indirectly, by affecting the production and decay of SM particles. The decay B0->K* mu mu is a flavor-changing neutral current (FCNC) process particularly sensitive, since it is heavily suppressed in the SM. Recent results from LHCb collaboration show a tension with respect SM prediction of more than 3 sigmas. We will present...
We report our recent results on rare radiative leptonic decays $B\to \gamma l^+ l^-$ ($l=\mu,e$) in the Standard Model. All necessary $B\to \gamma$ transition form factors induced by the flavour-changing axial, vector, tensor, and pseudo-tensor $b\to s,d$ transitions are calculated within the relativistic dispersion approach based on the constituent quark picture. Making use of the updated...
In the recent past, several hints of inconsistencies between experimental results and theory predictions in the framework of the Standard Model (SM) have been obtained from measurement of $B$-meson decays, though no beyond-SM (BSM) effects have been observed yet.
We report here about a few recent searches for BSM effects in B-meson decays performed with the full BaBar data sample, collected...
The Belle II experiment at the SuperKEKB collider is a major upgrade of the KEK ``B factory'' facility in Tsukuba, Japan. The machine is designed for an instantaneous luminosity of 8x10^35 cm^-2s^-1, and the experiment is expected to accumulate a data sample of about 50 ab^-1 in five years of running. With this amount of data, decays sensitive to physics beyond the Standard Model can be...
New and recent results from the ATLAS programme of studies in EW physics with open beauty are presented. FCNC processes are sensitive to NP contributions, in particular through additional electroweak loop amplitudes. The angular analysis of the decay of Bd -> K* mu mu for a number of angular coefficients are measured as a function of the invariant mass squared of the di-muon system for data...
I present results for the invariant and helicity amplitudes in the transitions
$\Lambda_b~\to~\Lambda^\ast(J^P)~+~J/\psi$ where
$\Lambda^\ast(J^P)$ are $sud$-resonances with
$J^P=\frac12^{\pm},\frac32^{\pm}$. The calculations are performed in
the framework of our covariant confined quark model.
We find that the values
of the helicity amplitudes for the $\Lambda^\ast(1520,\,\frac32^-)$
and...
I review theoretical progress in the study of semileptonic tree-level B decays and its interplay with recent experimental results. In particular, I focus on two anomalies: the ratios $R(D)$, $R(D^{*})$:
$R(D^{(*)})=\frac{BR(B-> D^{(*)} \tau \bar \nu_\tau)}{BR(B-> D^{(*)} \ell \bar \nu_\ell)}$
and the inclusive vs exclusive determination of $|V_{cb}|$.
I review several explanations for such...
LHC results on tree-level beauty decays
Tree-level beauty decays present crucial ingredients in the search for physics beyond the SM through quark flavour changing transitions.
This contribution covers recent LHC results in charged-current semileptonic decays and beauty decays to both charmed and charmless fully hadronic final states.
The semileptonic decays must be studied to determine the...
Rare B decays with leptons in the final state are powerful probes to search for physics beyond the Standard Model (SM) as they can be calculated in the SM with high precision. We report recent results on rare B decays with leptons from the Belle experiment at the KEKB $e^+ e^-$ collider. The $B \to D^* \tau^+ \nu$ mode is sensitive to New Physics effects such as a charged Higgs or leptoquark...
Due to their large branching fractions and good theoretical uncertainties, semileptonic b-hadron decays are excellent tools to study the CKM matrix and b-hadron properties such as lifetimes. The LHCb experiment has a very good potential for studies of semi-leptonic decays of b-hadrons, due to its excellent muon identification capabilities and very good reconstruction of decay vertices. In this...
We present recent results on the extraction of Vcb from data on B->D^* l nu decays. Using two different parameterizations of form factors, we show how theory input from Heavy Quark Effective Theory or Light Cone Sum Rules affect the value of Vcb. The results show that the inconsistency of Vcb extractions in exclusive and inclusive decays needs a reappraisal.
The CKM angle gamma is the least well-known angle of the unitarity triangle, and the only one easily accessible at tree level. Important constraints on gamma are obtained from time dependent analysis of flavour-tagged Bs -> Ds K decays, and the latest results using the full LHCb Run 1 dataset are presented here. The ultimate goal of degree level precision for gamma requires exploitation of all...
I present results of an analysis of scalar contributions in b→cτν transitions including the latest measurements of R(D(∗)), the q2 differential distributions in B→D(∗)τν, the τ polarization asymmetry for B→D∗τν, and the bound derived from the total width of the Bc meson. Scalar contributions with the simultaneous presence of both left- and right-handed couplings to quarks can explain the...
Charmless b-hadron decays are CKM suppressed in the Standard Model, which brings the tree amplitudes to levels comparable with corresponding loop amplitudes. Hence, new particles not foreseen in the SM that appear in the loops may alter observables of these decays. We present the most recent measurements of branching ratios and CP asymmetries in charmless b-hadron decays to two- and multi-body...
Three key issues pertaining to the semi-leptonic RD(*) anomalies will be addressed here:
1) How robust are the SM predictions?
2) What are the model-independent collider signature of these anomalies?
3) What are some of the simplest BSM explanations for these?
In answer to 1) latest information from on and off the lattice will be critically
examined to question, in particular the reliability...
The Belle II experiment is a substantial upgrade of the Belle detector; it will operate at the SuperKEKB energy-asymmetric e+e− collider. The detector is in its final phase of construction and the accelerator has successfully completed the first phase of commissioning. The design luminosity is 8×1035cm−2s−1, and the Belle II experiment aims to record 50 ab−1 of data, a factor of 50 more than...
Investigating the phenomenology of semileptonic $B_s$ meson decays allows to further constrain the Standard Model and explore new, independent channels to determine important parameters, like the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$. Given different systematics of $B_s$ decays w.r.t. $B$ decays, this may help to shed light on the long-standing discrepancy between inclusive and...
Motivated by the possible signals of lepton number violation in B physics, known as RD(*) and RK, RK$^*$ puzzles, we investigate whether
charm physics might offer a window to New Physics, too.
Relying on the existing lattice QCD and experimental results on charm leptonic and semileptonic weak decays, one can question presence of NP in the charge current transitions.
One can constrain the...
Measurements of CP- and flavour-violating transitions of charm and beauty hadrons are very powerful probes for physics beyond the standard model, that are complementary to the direct searches performed at the energy frontier. Experiments at the LHC are, since the start of Run 1 (2011-2012) playing a crucial role in this sector. The most recent highlights from LHCb, ATLAS and CMS are presented,...
The BESIII Experiment at the Beijing Electron Positron Collider
(BEPCII) accumulated the world's largest e+e- collision samples
at Ecm = 3.773, 4.009, 4.18 GeV. Based on analyses of D(s)+ to l+v
(l=mu, tau), D -> K(pi)l+v (l=e or mu), D+ -> K-pi+e+v, D0(+) ->
f0(980)e+v, Ds+ -> eta(')e+v, we report the determinations of CKM
matrix elements |Vcs(d)|,the D(s)+ decay constants, the form...
Time-dependent CP-violation measurements allows to determine the mixing-induced CP-violating phases phi_s and beta. The measurement of the phase phi_s in the Bs-Bsbar system is one of the key goals of the LHCb experiment. It has been measured at LHCb exploiting the Run I data set and using several decay channels. In particular, the most recent Run I results that will be presented at this...
The violation of CP symmetry is well established nowadays in the K and B mesons sectors. However CPV has not been observed in the baryonic sector. Charmless b-baryon decays represent a promising opportunity in this respect since their amplitudes receive contributions from tree level diagrams where the CKM element Vub appears. In addition, these decays are sensitive to possible physics beyond...
Rare charm decays offer a unique window to probe the up-type sector in flavor physics.
Motivated by the recent Belle measurement of the decay $D^0\to\rho^0\gamma$ we investigate its standard model contribution as well as physics beyond the standard model (BSM).
We study observables of rare radiative charm decays which are testable at colliders and identify possible effects BSM, in particular...
Following the hints for deviations from the Standard Model in rare B meson
decays, searches for rare and forbidden decays of charmed hadrons become a hot
topic again. We present recent results on rare D0 and Lc decays.
The question of the validity of analyzing charmed meson decays to pairs of mesons within the $SU(3)_F$ framework has been long and often debated. There are convincing arguments that small breaking of this symmetry can accommodate for the current experimental data on branching fractions of $D\to P P$ ($P=\pi,K,\eta$). However, the uncertainty in the evaluation of the amplitudes in these modes...
The measurement of the time-dependent CP violation parameters for B-meson decays is crucial for tightening the constraints on the unitarity triangle and for the search of new physics beyond the Standard Model.
A clean environment for the study of B decay channels is provided by B-factories. With a design luminosity of 8 · 10^35 cm^−2s^−1, leading ultimately to an integrated luminosity beyond...
We present the current status of the Unitarity Triangle Analysis in the Standard Model and in the presence of New Physics, as well as a global analysis of D meson mixing data. Based on these results, we obtain constraints on New Physics in Delta F = 2 processes and present bounds on the scale of New Physics.
Hadronic $B$ decays without a charm quark constitute a powerful probe to search for
physics beyond the standard model as well as provide constraints of $CP$-violation
parameters. We report the final measurements from Belle of the branching fraction
and $CP$ asymmetry for the decays $B^{0}\to \pi^{0}\pi^{0}$, $B^{\pm}\to
K^{+}K^{-}\pi^{\pm}$ and preliminary results for $B^\pm\to...
Using more than $920 {\rm fb}^{-1}$ data collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider, we report the first measurement of the T-odd moments in the decay $D^0 \to K_S^0 \pi^0 \pi^+ \pi^-$ and the first observation of the radiative charm decay $D^0 \to \rho^0 \gamma$. We search for CP-violation in decays $D^0 \to K_S^0 K_S^0$, $D^+ \to \pi^+ \pi^0$, $D^0 \to...
Being able to predict a small set of hadronic observables precisely and more importantly reliably
in lattice QCD has been a big achievement (see Flavour Lattice Averaging Group review). Decreasing the precision
below the %-level and increasing the set of numbers for which predictions can be made is challenging
but exciting. This talk will highlight recent conceptual progress on hadronic...
K->pinunu is one of the theoretically cleanest meson decay where to look for indirect effects of new physics complementary to LHC searches. The NA62 experiment at CERN SPS is designed to measure the branching ratio of the K+->pi+nunu decay with 10% precision. NA62 took data in 2015 and 2016 reaching the Standard Model sensitivity. The KOTO experiment in Japan is investigating the decay K0->pi0...
We present the most recent data from the engineering run at FNAL of the new g-2 experiment. The method of extracting the anomalous magnetic moment is summarized and the improvements implemented in the new experimental beam delivery, storage ring, detectors and analysis techniques are discussed. The current understanding of the systematics from the experiment and theory are presented together...
Using new hadronic cross section data for more than 10 exclusive channels mainly from Babar in the energy range up to 2 GeV and also from VEPP-2000, the hadronic contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the Z-boson mass are updated. The new data complement the previously available information on exclusive channels allowing to...
The search for the Lepton Flavor Violating decays $\mu^+ \to e^+ \gamma$ and $\mu^+ \to e^+ e^+ e^-$ will reach an unprecedented level of sensitivity within the next five years thanks to the MEG-II and Mu3e experiments. These experiments will take data at the Paul Scherrer Institut where continuous muon beams are delivered at a rate of about $10^8$ muons per seconds. On the same time...
The KLOE-2 experiment at the INFN Laboratori Nazionali di Frascati
(LNF) is currently taking data at the e+e- DAFNE collider which is implementing an innovative collision scheme based on a crab-waist configuration.
An integrated luminosity of 3.5 fb-1 has been already collected by KLOE-2, and at least 5 fb−1 are expected by Spring 2018.
KLOE-2 represents the continuation of KLOE with an...
Combining Pati-Salam (PS) and flavour symmetries in a renormalisable setup,
we devise a scenario which produces realistic masses for the charged
leptons. Flavour-symmetry breaking scalar fields in the adjoint
representations of the PS gauge group are responsible for generating different
flavour structures for up- and down-type quarks as well as for leptons.
The model is characterised by new...
Rare decays are fundamental probes of physics beyond the Standard Model.
The expanding LHCb program of strange physics, in particular of their rare decays, provides a unique and complementary probe to test the SM with respect to the beauty and charm sector.
We present here the current status of rare decays studies at the LHCb experiment, including the new limit on the Ks -> mu mu branching...
Recently, the standard model prediction of $\epsilon'/\epsilon$ was
improved, and a discrepancy from the experimental results was reported
at the $2.9\sigma$ level. We study the charging contributions to $Z$
penguin especially with the vacuum stability constraint. The vacuum
decay rate is investigated, and it is shown that the discrepancy can be
explained if super particles are lighter...
The Mu2e experiment aims to measure the charged-lepton flavour violating (CLFV) neutrino-less conversion of a negative muon into an electron in the field of a nucleus. The conversion process results in a monochromatic electron with an energy slightly below the muon rest mass (104.97 MeV). Goal of the experiment is to improve of four orders of magnitude the previous measurement and reach a...
The NA48/2 experiment presents a final result of the charged kaon semileptonic decays form
factors measurement based on 4.28 million $K^\pm_{e3}$ and 2.91 million $K^\pm_{\mu 3}$ selected
decays collected in 2004. The result is competetive with other measurements in $K^\pm_{\mu 3}$
mode and has a smallest uncertainty for $K^\pm_{e3}$, that leads to the most precise
combined $K^\pm_{l3}$...
