Conveners
Quark and Lepton Flavor Physics: 1
- Margarida Nesbitt Rebelo (Instituto Superior Tecnico (IST))
Quark and Lepton Flavor Physics: 2
- Phillip Urquijo (University of Melbourne (AU))
Quark and Lepton Flavor Physics: 3
- Margarida Nesbitt Rebelo (Instituto Superior Tecnico (IST))
Quark and Lepton Flavor Physics: 4
- Olivier Leroy (Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France)
Quark and Lepton Flavor Physics: 5
- Chris Parkes (University of Manchester (GB))
Quark and Lepton Flavor Physics: 6
- Phillip Urquijo (University of Melbourne (AU))
Quark and Lepton Flavor Physics: 7
- Leo Piilonen (Virginia Tech)
Quark and Lepton Flavor Physics: 8
- Chris Parkes (University of Manchester (GB))
Quark and Lepton Flavor Physics: 9
- Thomas Browder (University of Hawaii)
Quark and Lepton Flavor Physics: 10
- Giovanni Passaleva (INFN Florence (IT))
Quark and Lepton Flavor Physics: 11
- Angela Papa
Quark and Lepton Flavor Physics: 12
- Angela Papa
Radiative b-hadron decays are sensitive probes of New Physics through the study of branching fractions, CP asymmetries and measurements of the polarisation of the photon emitted in the decay. During Run-1 of the LHC, the LHCb experiment has collected large samples of radiative b-hadron decays. We present here the latest LHCb measurements, which help constrain the size of right-handed currents...
The b→s gamma process is sensitive to new physics since the new heavy particles can enter in the loop and thus change the branching fractions, CP asymmetry or other kinetic variables. We present on measurement of the CP asymmetry and isospin asymmetry of B → Xs gamma and B → K* gamma, and also their difference of CP asymmetry between charged and neutral modes. The analyses are based on the...
With the large integrated luminosity collected and the high efficiency of its di-muon triggers, the CMS experiment is a privileged test bench for rare decays involving heavy flavors. We report about the most recent measurements based on LHC Run 2 data, including decays of B and tau particles to muons and rare vector boson decays to heavy flavors.
The quark and lepton mass patterns upset their naive unification. In this talk, a new approach to solve this problem is described. Model-independently, we find that a successful unification can be achieved. A mechanism is identified by which the large top quark mass renders its third-generation leptonic partner very light. This state is thus identified with the electron. We then provide a...
Angular analyses of penguin B hadron decays such as B0->K ll constitute one of the main indirect probes of new physics at LHC, due to the clean theoretical predictions and precise experimental results that can be obtained. In this report we present the most recent results of the CMS experiment on this subject, including the measurement of the P1 and P5’ angular variables in B0->Kmumu decays...
The ATLAS experiment has performed accurate measurements of mixing and CP violation in the neutral B mesons, and also of rare processes happening in electroweak FCNC-suppressed neutral B-mesons decays. This talk will focus on the latest results from ATLAS, such as rare processes: B^0_s → mu mu and B^0 → mu mu; and CPV in Bs to Jpsi Phi
The electroweak penguin B decay process b → s l+ l- is a sensitive probe to New Physics (NP) Recent measurements of angular variable of B → K* l+ l- by LHCb and Belle indicate a deviation from the standard model, and further measurements on these process are of interest in the search of NP. In this presentation, we report on the measurements of lepton flavor non universality tests and search...
The coupling of the electroweak gauge bosons of the Standard Model (SM) to leptons is lepton flavour universal. Extensions of the SM do not necessarily have this property. Rare decays of heavy flavour are heavily suppressed in the SM and new particles can give sizeable contributions to these processes, their precise study thus allows for sensitive tests of lepton flavour universality. Of...
Recent hints for lepton-universality violation in b->clnu and b->sll transitions could imply the existence of lepton-flavour violating B decays. The LHCb experiment is well suited for the search for these decays due to its large acceptance and trigger efficiency, as well as its excellent invariant mass resolution and particle identification capabilities. Recent results on searches for...
Rare b->sll 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 their angular distributions. The LHCb experiment is ideally suited for the analysis of these decays due to its high trigger...
We search for the rare flavor-changing neutral current process $B^- \to \Lambda \bar{p} \nu \bar{\nu}$ using data from the BABAR experiment. A total of 424fb$^{−1}$ of $e^+e^−$ collision data collected at the center-of-mass energy of the $\Upsilon(4S)$ resonance is used in this study, corresponding to a sample of $(471\pm3)\times 10^6$ $B-\bar{B}$ pairs. Signal $B^- \to \Lambda \bar{p} \nu ...
The anomalies recently observed in b→sμμ data could be early signals of physics beyond the standard model (SM) in b→s transitions. Assuming this to be the case, we consider a scenario in which a Z' boson is responsible for the anomalies. We further assume that its interactions also affect rare nonleptonic decays of the Bs meson which tend to be dominated by...
Rare semileptonic $b \to s \ell^+ \ell^-$ transitions provide some of the most promising framework to search for New Physics effects.
Recent analyses have indicated an anomalous pattern in measurements of lepton-flavour-universality observables.
We propose a novel approach to independently and complementary clarify the nature of these effects
by performing a simultaneous amplitude...
In the Standard Model, the three charged leptons are identical copies of each other, apart from mass differences. Experimental tests of this feature in semileptonic decays of b-hadrons are highly sensitive to New Physics particles which preferentially couple to the 2nd and 3rd generations of leptons. This talk will review the latest lepton universality tests in semileptonic b->c transitions at LHCb.
Exclusive semileptonic b-hadron decays are under good theoretical control, which allows precise determinations of the CKM matrix elements, Vub and Vcb. The large production of Lambda_b baryons and Bs mesons at the LHC allows LHCb to provide complementary information with respect to the B-factories in this sector, as well as in the measurement of the shape of the Lambda_b differential decay...
The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+ e^-$ collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and first electron positron collisions in Belle II are expected for April 2018. The design luminosity of SuperKEKB is $8 \times 10^{35}$ cm$^{-2}$s$^{-1}$ and...
Recent measurements of the properties of heavy flavor particles at CMS, based on data collected at Run 1 and Run 2 of the LHC, are presented. Reported results include, among the others, measurements of lifetimes, masses and branching ratios of B hadrons and heavy quarkonia.
New LHCb results in the measurement of B meson mixing parameters and branching fractions will be presented. The results are obtained using pp collisions collected in Run 1 and Run 2 of the LHC and include a new and world's most precise determination of the decay width difference in the Bs system and the ratio between the decay width of the Bs and Bd mesons.
We report measurements of sin2beta = sin2phi_1 and cos2beta = cos2phi_1 from a time-dependent Dalitz analysis in B^0 to D^{(*)0} h^0 with D to K^0_S pi^+ pi^- decays using BaBar and Belle combined data sample containing 471 + 772 million B meson pairs collected at the Upsilon(4S) resonance. The measurement gives a confirmation of the CP violation in this B decay mode and solves the two-fold...
Time-dependent CP violation in B->DX decays provides sensitivity to angles of the CKM matrix. The excellent time resolution of the LHCb detector provides opportunities to perform precise time-dependent measurements. A summary of recent LHCb results are presented, including the B0->Dpi analysis which profits from the largest flavour tagged sample analysed by LHCb to determine the CKM angle sum...
We report measurements of time-dependent CP violation in charmless B meson decays that are sensitive to physics beyond the Standard model or Kobayashi-Maskawa CP violation angle phi_2 in b to s penguin or b to u tree transitions, respectively. The analyses use Belle final entire data sample collected at the Upsilon(4S) resonance containing 772 mullion B meson pairs.
Precision measurements of time-dependent CP violation and of mixing parameters in the neutral B meson systems are bound to the ability to identify the production flavour of reconstructed b hadrons. The harsh environment of proton-proton collisions at LHC constitutes a challenging environment for flavour tagging and demand for novel and improved strategies. We present recent progress and new...
Precision measurements of CP violating observables in b hadron decays with charmonia in the final state are powerful probes to search for physics effects beyond the Standard Model. The most recent results on CP violation in the decay, mixing and interference of b hadrons obtained by the LHCb Collaboration will be presented, with particular focus on results obtained exploiting the data...
Time dependent CP-violation phenomena are a powerful tool to precisely measure fundamental parameters of the Standard Model and search for New Physics. The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+ e^-$ collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and...
The amplitudes governing the decays of neutral b-hadrons to charmless charged two-body final states receive relevant contribution from both b->u tree-level and b->d,s penguin topologies. Hence, these decays are sensitive probes of the CKM paradigm, but also have the potential to reveal new physics beyond the Standard Model. Relevant quantities to measure are time-dependent and time-integrated...
Decays of b-mesons to charmless multi-body final states are CKM suppressed in the Standard Model, which brings the tree amplitudes to levels comparable with corresponding loop amplitudes. New particles not foreseen in the SM that appear in the loops may alter not only the CP asymmetries of these decays, but also the polarisation fractions and triple-product asymmetries. The latest measurements...
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 both contributions from tree level diagrams where the CKM element Vub appears and loop level diagrams which have comparable contirbutions. In...
Charmless three-body decays of B mesons are an ideal place to study CP violation, as contributions from 'loop' diagrams at a similar magnitude to tree-level diagrams, and variation of the strong phase across the so-called 'Dalitz plot', can result in phase-space regions with large CP asymmetries. Furthermore, many of these decays can be used to inform determinations of the angles of the...
The CKM angle gamma remains the least precisely measured angle of the unitarity triangle, and is the only easily accessible with purely tree level decays, making it a benchmark for Standard Model flavour processes. We present the Run 2 update of the measurement of gamma using the GGSZ method with the golden mode B+->DK+, D->Kshh. The results of the latest LHCb gamma combination are also shown,...
Measurements of charge CP asymmetries in the decays of b hadrons with charmonia in the final state are powerful probes to search for physics effects beyond the Standard Model. Recent results in the measurement of direct CP violation of B mesons performed by the LHCb collaboration using Run 1 data will be presented.
Direct CP violation in B meson decays provides a good probe for New Physics. We report measurement of branching fraction(BF) and direct CP asymmetries (Acp) in charmless B decays B+ → KsKsK+ and B+ → KsKspi+, which proceed through b→s and b→d flavor-changing neutral current transitions, respectively. Another charmless B decay B0 → K-pi+Ks, which proceeds through b→d penguin process, is also...
Measurements of CP violation are a core part of the LHCb physics programme to over constrain the CKM matrix and to understand the differences between matter and antimatter. The worlds most precise measurement of ACP in B+->DD0 decays is presented alongside the first measurement of ACP in the B+->DsD0 channel. Results from B(s)->D0KK decays are also shown, including the first observation of the...
Two of the most powerful methods currently used to determine the angle γ of the CKM Unitarity Triangle exploit B+→DK+, D→K0Sπ+π− decays and B0→DK+π−, D→K+K−, π+π− decays. It is possible to combine the strengths of both approaches in a “double Dalitz plot” analysis of B0→DK+π−, D→K0Sπ+π− decays. The potential sensitivity of such an analysis is investigated in the light of recently published...
The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+ e^-$ collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and first electron positron collisions in Belle II are expected for April 2018. The design luminosity of SuperKEKB is $8 \times 10^{35}$ cm$^{-2}$s$^{-1}$...
BESIII collected 2.93 and 3.2 fb$^{-1}$ of data at $\sqrt(s) = 3.773$ and 4.178 GeV, respectively. Many hadronic decays of $D^{0(+)}$ and $D_s^+$ have been studied. In this talk, the measurements of the branching fractions of $D^{0(+)} \to PP$ (P=Peudecalor) decays, the observations of the baryonic decay $D_s^+ \to p\bar{n}$ and the pure W-annhilation decay $D_s^+ \to \omega \pi^+$ as well as...
LHCb has collected the world's largest sample of charmed hadrons. This sample is used to measure $D^0- \bar D^0$ mixing and to search for indirect CP violation. New measurements from several decay modes are presented, as well as prospects for future sensitivities.
LHCb has collected the world's largest sample of charmed hadrons. This sample is used to measure direct CP violation in D0 mesons and Lc baryons. New measurements from several decay modes are presented, as well as prospects for future sensitivities.
Using more than 920fb-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 D0→KS0π0π+π- . We search for CP-violation in decays D0→KS0KS0 and D+→π+π0 . All the results are consistent with no CP violation. We also report the result from the first search for D0 decays to invisible final states. No...
BESIII accumulated the world largest samples of $e^+e^-$ collision at $\sqrt(s) = 3.773$ and 4.178 GeV. The purely leptonic decays $D^+_{(s)} \to l^+\nu$, and the semi-leptonic decays of $D^0 \to K(\pi)^-e^+\nu$, $K(\pi)^-\mu^+\nu$, $\rho^- e^+\nu$; $D^+ \to K^0(\pi^0)e^+\nu$, $K^0(\pi^0) \mu^+\nu$; $D_s^+ \to K^{(*)0}e^+\nu$ and $\eta^{(')}e^+\nu$ have been studied. We will report the...
The BESIII detector accumulated 567 pb$^{-1}$ of data at the center-of-mass energy of 4.6 GeV, which is the world's largest $e^+e^-$ sample at the $\Lambda_c$ pair threshold. By analyzing this data sample, we report the determinations of the absolute branching fractions of the semi-leptonic decays of $\Lambda_c^+ \to \Lambda e^+\nu$ and $\Lambda \mu^+\nu$, the hadronic decays of $\Lambda_c^+...
LHCb is playing a crucial role in the study of rare and forbidden decays of charm hadrons, which might reveal effects beyond the Standard Model. New searches for FCNC mediated processes and first asymmetry measurements in multibody final states with two leptons are presented.
Flavor-changing neutral current (FCNC) processes are rare within the Standard Model (SM) as they cannot occur at tree level and are suppressed at loop level by the Glashow-Iliopoulos-Maiani (GIM) mechanism. In $D$-meson decays, the GIM cancellation is almost exact, leading to expected branching fractions for $c\to u l^- l^+$ processes of order $\mathcal{O}(10^{-9})$. However, long-distance...
The Flavor Changing Neutral Current decays(FCNC) are forbidden at tree level in the Standard Model (SM) and could only contribute through loops. Any direct observation beyond the SM expectations could be a good probe of physics beyond the SM. BESIII is the only currently running tau-charm factory with the largest samples of on threshold charm meson pairs, directly produced charmonia and some...
The KOTO experiment aims to observe the K$^{0}_{L} \rightarrow \pi^{0}\nu\bar{\nu}$ decay and measure the branching rate. The Standard Model (SM) prediction for the mode is 2.4 x 10$^{-11}$ with a small theoretical uncertainty. An experimental upper limit of 2.6 x 10$^{-8}$ was set by the KEK E391a collaboration [1]. A comparison of experimentally obtained results with SM calculations permits...
The KOTO experiment is dedicated to observing the rare decay $K_L\rightarrow\pi^{0}\nu\bar{\nu}$ at the J-PARC 30 GeV proton synchrotron. This decay breaks the CP symmetry directly and is highly suppressed in the Standard Model. Thus this decay mode is sensitive to new physics beyond the SM, in particular the physics related to CP violation.
Data collected in 2013 were analyzed and published...
Precise measurements of the branching ratios (BRs) for the flavor-changing neutral current decays $K\to\pi\nu\bar{\nu}$ can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. It is important to measure both decay modes, $K^+\to\pi^+\nu\bar{\nu}$ and $K_L\to\pi^0\nu\bar{\nu}$, since different new physics models affect the rates for each channel differently....
We present a measurement of the charged kaon semileptonic form factors based on 4.3 million $K^\pm \rightarrow \pi^0 e^\pm \nu_e$ and 2.1 million $K^\pm \rightarrow \pi^0 \mu^\pm \nu_{\mu}$ decays collected by the NA48/2 experiment. The single results for the semi-electronic and semi-muonic channel have better and similar precision, respectively, than previous measurements. The combination of...
The KLOE-2 experiment is finalizing data taking at the upgraded e+e- DA$\Phi$NE collider of the INFN Laboratori Nazionali di Frascati, collecting more than 5 fb$^{-1}$ at the center of mass energy of the $\phi$ meson. Together with the data sample collected by its predecessor KLOE, the total of almost 8 fb$^{-1}$ integrated luminosity represents the largest existing data sample in the world...
The search for the Lepton Flavor Violating decay $\mu \to e \gamma$ exploits the most intense continuous muon beams, which can currently deliver $\sim 10^8$ muons per second. In the next decade, accelerator upgrades are expected in various facilities, making it feasible to have continuous beams with an intensity of $10^9$ or even $10^{10}$ muons per second. We investigate the experimental...
The Mu3e experiment searches for the charged lepton flavour violating μ+ → e+e+e− decay and it aims at reaching an ultimate sensitivity of 10^−16 on the branching frac- tion of the μ+ → e+e+e− decay, four orders of magnitude better than the current limit B(μ+ → e+e+e−) < 10^−12. The experiment will be hosted at the Paul Scherrer Institute (Villigen, Switzerland) which delivers the most intense...
Mu2e will search for coherent, neutrino-less conversion of muons into electrons in the field of a nucleus with a sensitivity improvement of a factor of 10,000 over existing limits. Such a charged lepton flavor-violating reaction probes new physics at a scale unavailable with direct searches at either present or planned high energy colliders. The experiment both complements and extends the...
Muon to electron conversion in a muonic atom is a process of charged lepton flavor violation (CLFV). It is not allowed in the Standard Model (SM) and known to be one of the best processes to search for new physics beyond the SM. The COMET experiment aims to search for this process at J-PARC with single-event sensitivity of $3\times10^{-17}$, which is about 10,000 improvement over the current...
Charged lepton flavor violation (CLFV) is a good probe for new physics beyond the
standard model of elementary particle physics.
The DeeMe experiment is going to search for one of the CLFV precesses, mu-e conversion in a nuclear field, with a sensitivity of 10^-14, ten times higher than current limits.
The experiment utilizes a fast-extracted proton beam from a Rapid Cycling Synchrotron (RCS)...
We evaluate the Michel parameters of τ decays using the full data sample of Belle. This is important to reveal the Lorentz structure of τ leptonic decays, which includes not only the V - A interaction but also contributions from scalar, tensor and others that may arise from New Physics, thus testing lepton universality as well. We use both tau+ → l+ nu nu and tau+ → l+ gamma nu nu. We also...
We report on the most recent results of studies of tau-lepton decays, relying on about $430\times10^6$ $e^+e^- \to \tau^+\tau^-$ events produced at a center-of-mass energy near 10.6 GeV with the BABAR detector at the PEP-II $e^+e^-$ collider.
We present measurements of the branching fractions and the spectral functions for the processes $\tau^{-}\to K^{-}K_S (\pi^{0}) \nu_\tau$, which can be...
Many new physics scenarios beyond the Standard Model often necessitate the existence of a (light) neutral scalar H, which might couple to the charged leptons in a flavor violating way, while evading all existing constraints. Such scalars could be effectively produced at future lepton colliders like CEPC, ILC and FCC-ee, either on-shell or off-shell, and induce lepton flavor violating (LFV)...
We investigate charged lepton flavor violating processes $\mu\rightarrow e \gamma$, $\mu\rightarrow e e \overline{e}$ and $\mu-e$ conversion in nuclei for a class of three-loop radiative neutrino mass generation models with electroweak multiplets of increasing order. We find that, because of certain cancellations among various one-loop diagrams which give the photonic dipole and non-dipole...
The CMD-3 experiment at the VEPP-2000 collider in Novosibirsk carries out a comprehensive study of the exclusive cross-sections of e+e- -> hadrons in the center-of-mass energy range from the threshold to 2E<2 GeV. The CMD-3 results provide an important input for calculation of the hadronic contribution to the muon anomalous magnetic moment. Currently there are world-wide efforts to improve the...
