Description
Conveners:
- Marcella Bona (Queen Mary University of London)
- Claudia Cornella (CERN)
- Diego Guadagnoli (LAPTh Annecy)
- Maria Vieites Diaz (IGFAE, Universidade de Santiago de Compostela)
Contact: eps-hep2025-conveners-T07-l@in2p3.fr
Electric dipole moments (EDMs) of elementary particles violate time-reversal symmetry. According to the CPT theorem, this also implies the violation of combined charge-conjugation and parity-inversion (CP) symmetry, making EDMs powerful tools for probing physics beyond the current Standard Model (SM) of particle physics.
The muEDM experiment at PSI aims at setting the ground for a new...
The search for electric dipole moments (EDMs) remains one of the most sensitive probes of CP violation and physics beyond the Standard Model. In this talk, I will present results from lattice QCD calculations of the neutron EDM induced by the QCD $\theta$-term. I will also discuss hadronic matrix elements of CP-violating effective operators relevant to BSM scenariosโkey theoretical inputs...
While CP violation (CPV) is well established in meson decays, its observation in baryon decays remains an open challenge. The LHCb experiment, designed to study CP violation in particles containing bb quarks, has collected an unprecedented dataset, offering a unique opportunity to probe CP asymmetries in baryon decays. This talk will present the latest LHCb results on CPV in baryon decays,...
The Belle and Belle II experiment have collected a 1.2 ab$^{-1}$ sample of $e^+e^-\to B\bar{B}$ decays at a centre-of-mass energy corresponding to the $\Upsilon(4S)$ resonance. The SuperKEKB collider is asymmetric, providing a boost to the $B$ mesons in the laboratory frame, so we can perform measurements of time-dependent $C\!P$ violation. Among the new results, we measure $CP$-violating...
$B$-meson decays into two vector mesons, $B \to VV$, constitute a class of decays of special interest. These decays are generally mediated by both loop and tree processes, making the measurement of their CP asymmetries, polarisation variables, and branching fractions especially interesting and challenging. For $B \to VV$ decays, any enhancement in one of those variables would be a hint for new...
In this talk we aim to summarize and give an overview of the status of heavy flavour related searches and measurements in CMS. The results will include analyses from rare decays, lepton flavour violation, and measurements of production cross sections.
This talk reports the result of the latest search for $\mu\to e\gamma$, which measured $1.3\times 10^{13}$ muon decays in the MEG II data collected in 2021-2022. A sensitivity of $2.2\times10^{-13}$ was achieved in this search, which is factor of 2.4 higher sensitivity than the previous experiment. In addition to the result, this talk discusses the status and prospect of the MEG II experiment,...
The Belle and Belle II experiments have collected a 1.2 ab$^{-1}$ sample of $e^+ e^-\to B\bar{B}$ collisions at a centre-of-mass energy corresponding to the $\Upsilon(4S)$ resonance. These data, with low particle multiplicity and constrained initial state kinematics, are an ideal environment to search for rare electroweak penguin $B$ decays and lepton-flavour-violating $B$ decays to final...
The Belle and Belle II experiments have collected a $1.6~\mathrm{ab}^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon(nS)$ resonances. This sample contains approximately 1.5 billion $e^+e^-\to \tau^+\tau^{-}$ events, which we use to search for lepton-flavour violating decays. We present searches for $\tau\to\ell\gamma$, tau decay to three charged leptons,...
Results are presented on LF(U)V tests through precise measurements of decays involving heavy mesons and leptons, which are compared to the standard model predictions. The measurements use pp collision data collected by the CMS experiment at the LHC.
Rare kaon decays are among the most sensitive probes of both heavy and light new physics beyond the Standard Model description thanks to high precision of the Standard Model predictions, availability of very large datasets, and the relatively simple decay topologies. The NA62 experiment at CERN is a multi-purpose high-intensity kaon decay experiment, and carries out a broad rare-decay and...
We update our combined analysis of D meson mixing and B decays sensitive to the CKM angle gamma including the latest experimental results. We derive constraints on absorptive and dispersive CP violation by combining all available data, and discuss future projections. We also provide posterior distributions for gamma and for the observable parameters appearing in D physics.
The Belle and Belle II experiments have collected a $1.6$ ab$^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon(nS)$ resonances. These samples contain a large number of $e^+e^-\to c\bar{c}$ events that produce charmed mesons. We present measurements of charm-mixing parameters from flavour-tagged $D^0\to K^0_{\rm S}\pi^+\pi^-$ decays. Direct $C\!P$ violation...
The LHCb experiment published the first observation of CP violation in the decay of charmed particles in 2019, using the decay channels $D^0 \to \pi^+\pi^-$ and $D^0 \to K^+K^-$. Additional measurements of $D^0$ mixing and of other decay channels are essential to understand whether this observation can be explained within the Standard Model, or if new sources of CP violation are needed. We...
In this talk I will discuss recent advances made in the calculation of the NNLO QCD corrections to the width difference between B and anti-B mesons. This work focuses on the perturbative high-energy part of the calculation, more specifically the matching coefficients between the $\Delta B = 1$ effective operators of the Weak Interaction and the $\Delta B = 2$ transition operator are calculated...
We present a novel approach to calculate heavy meson lifetimes on the lattice. To tackle this long standing problem, we utilize gradient flow in combination with the short flow time expansion to nonperturbatively renormalize our lattice results and perform a perturbative matching to the $\overline{\textrm{MS}}$ scheme. This paves the way to circumvent challenges on the lattice such as mixing...
The Belle and Belle II experiments have collected a 1.2 ab$^{-1}$ sample of $e^+ e^-\to B\bar{B}$ collisions at a centre-of-mass energy corresponding to the $\Upsilon(4S)$. The study of hadronic $B$ decays in these data allow the precise measurement of absolute branching fractions and angular distributions of the decay products. These measurements provide tests of QCD and allow the generation...
The results of the tau branching fraction fit performed by HFLAV (also reported in the PDG Review of Particle Physics) are used to update the Lepton Universality tests and to calculate Vus using tau measurements. The lepton universality tests that rely on the leptonic tau branching fractions are updated to the 2nd order QED radiative corrections, in preparation for future improved precision...
The first run of the Belle II experiment collected a 365 fb$^{-1}$ sample of $e^+ e^-\to B\bar{B}$ collisions at a centre-of-mass energy corresponding to the $\Upsilon(4S)$ resonance. These data, with low particle multiplicity, constrained initial state kinematics and excellent lepton identification, are an ideal environment to study lepton-flavour universality in semileptonic decays of the...
Lepton flavour plays a crucial role in tests of the Standard Model and searches for New Physics. Within the Standard Model, the electroweak bosons couple universally to the three lepton families, differing only by mass effects (Lepton Flavour Universality, LFU) --- charged Lepton Flavour Violation (cLFV) is highly suppressed. However, several beyond-the-Standard-Model scenarios predict...
Semileptonic $b$-hadron decays proceed via charged-current interactions and provide powerful probes for testing the Standard Model and searching for New Physics effects. The advantages of studying such decays include the large branching fractions and reliable calculations of the hadron matrix elements. Several SM features may be studied, such as the CKM parameters, the properties of $b-$hadron...
The Belle and Belle II experiments have collected a combined sample of 1.2~ab$^{-1}$ of $e^+ e^-\to B\bar{B}$ collisions at a centre-of-mass energy corresponding to the $\Upsilon(4S)$ resonance. These data, with low particle multiplicity and constrained initial state kinematics, are an ideal environment for studying semileptonic and leptonic decays of the $B$ meson. Combined with...
The Future Circular Collider (FCC) is a post-LHC project aiming at direct and indirect searches for physics beyond the SM in a new 91 km tunnel at CERN. The abundant production of beauty and charm hadrons in the $8\times 10^{12}$ Z boson decays expected in e+e- collisions at FCC-ee offers outstanding opportunities in flavour physics with b and c hadron samples that exceed those available at...
This spring, Fermilab's "Muon g-2" experiment is set to unveil its final results, targeting an unprecedented precision of 0.1 parts per million in measuring the muon's anomalous magnetic moment. To fully leverage this measurement in the quest for new fundamental physics, minimizing uncertainties in the Standard Model prediction is essential. This talk will review the various contributions to...
In this talk, we present a recent lattice calculation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon, by the Budapest-Marseille-Wuppertal collaboration. Together with the hadronic vacuum polarization, this is the dominant source of uncertainty in the Standard Model prediction. We will compare our result with previous lattice calculations and...
Recent measurements of the anomalous magnetic moment of the muon have challenged the Standard Model, producing significant tensions between theory and experiment. Accurate theoretical predictions are difficult due to the strongly interacting nature of QCD, which is the primary source of uncertainty in the Standard Model prediction for the muon g-2. In this talk, we present a lattice QCD...
This work achieves the first analytical determination of the three-loop hadronic vacuum polarization contribution to the muon's anomalous magnetic moment ($gโ2$). Leveraging cutting-edge amplitude techniques within chiral perturbation theory, the effective field theory for low-energy QCD, we present this infinite volume calculation. Our result is crucial for accurately estimating finite volume...
The Fermilab Muon $g-2$ Experiment is designed to measure the muon's anomalous magnetic moment, $ a_\mu = (g-2)/2 $ with a final accuracy of 140 parts per billion. This quantity is determined from two key measurements; the magnetic field and the difference between the muon's spin precession frequency and its cyclotron frequency, given by $\omega_a = \omega_s - \omega_c$, in a highly uniform...
The Fermilab Muon g-2 experiment is designed to determine the muonโs magnetic moment anomaly with an unprecedented precision of 0.14 parts per million (ppm). This anomaly is extracted from the ratio of the muonโs anomalous spin precession frequency within a magnetic storage ring to the magnetic field experienced by the ensemble of muons. However, the measured precession frequency is subject to...
We describe how several highly correlated measurements of the muon precession frequency in magnetic field by multiple independent analysis groups were checked for consistency and averaged, for the final measurement of the muon magnetic anomaly by the FNAL muon g-2 experiment. With a significant improvement with respect to the past data analyses of the experiment, we planned the use of common...
BESIII has collected 20.3 and 7.33 $fb^{-1}$ of $e^+e^-$ collision data samples at 3.773 and 4.128-4.226 GeV, which provide the largest dataset of $D\bar{D}$ and $D_sD_s$ pairs in the world, respectively.
We will present the measurement of branching fractions of fifteen $D_s^+$ hadronic decays using a global fit and highlight our recent advancements in amplitude analyses of $D^+ \to K_s \pi^+...
BESIII has accumulated 4.5 fb^-1 of e+e- collision data in the 4.6 and 4.7
GeV energy range, which provides the largest dataset of Lambda_c- Lambda_c
pairs in the world.
Our presentation will include the observation of a rare beta decay of the
charmed baryon Lambda_c+ -> n e+ nu with a Graph Neural Network and the
first measurement of the decay asymmetry in the pure...
BESIII has recently accumulated a large data sample at the $\psi(3770)$ energy point corresponding to an integrated luminosity of 20 $fb^{-1}$. The neutral $D \bar{D}$ pairs produced at $\psi(3770)$ are in a C-odd correlated state, providing a unique laboratory to measure the strong-phase differences between $D^0$ and $\bar{D}^0$ decays. These parameters are essential inputs to CP violation...
The Belle and Belle II experiments have collected a $1.6 \mathrm{ab}^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon(nS)$ resonances. These samples contain a large number of $e^+e^-\to c\bar{c}$ events that produce charmed mesons and baryons. We present searches for rare flavour-changing neutral current processes and measure several radiative decays of...
This talk will present the recent results from ATLAS experiments on open-charm meson production measurements and various studies of b hadron decays, including the most precise measurement of the $B^0$ lifetime.
The $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay is a golden mode for flavour physics. Its branching ratio is predicted with high precision by the Standard Model to be less than $10^{-10}$, and this decay mode is highly sensitive to indirect effects of new physics up to the highest mass scales. A new measurement of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay by the NA62 experiment at the...
Rare kaon decays offer a sensitive window into short-distance physics and potential signals of physics beyond the Standard Model (BSM). This work focuses on several key decay modesโnamely $K^+ \to \pi^+ \nu\bar{\nu}$, $K_L \to \pi^0 \nu\bar{\nu}$, and $K_L \to \pi^0 \ell^+ \ell^-$โhighlighting how new physics scenarios can influence their behavior. We perform a global analysis of current rare...
Flavour-changing neutral current processes, such as $b\to s\ell^+\ell^-$ and $b\to d\ell^+\ell^-$ transitions, are highly sensitive probes of new physics. In the Standard Model, their contributions are both loop and CKM suppressed, with $b\to d\ell^+\ell^-$ further suppressed by small off-diagonal quark-flavour mixing couplings and forbidden at the lowest perturbative order. The $b\to...
In recent years the LHCb experiment has expanded its physics reach to searches for $K_{\rm S}$ and hyperon rare decays, and is currently the experiment with the highest yields of reconstructed decays of these particles. Particularly, searches for flavour changing neutral currents have been performed, sensitive to physics beyond the Standard Model. The $K_{\rm S}\to \mu^+ \mu^-$ and $K_{\rm...
We discuss the role of Flavour physics in global fits of dimension-six operators in the Standard Model Effective Theory. We present results from fits with different assumptions on the SMEFT flavour structure: U(3)^5, U(3)^5 and Minimal Flavour Violation. The leading-order scale dependence of the SMEFT Wilson coefficients is consistently included in the evolution from the UV scale to the...
Flavour physics represents a unique test bench for the Standard Model (SM). New analyses performed at the LHC experiments and new results coming from Belle II are bringing unprecedented insights into CKM metrology and new results for rare decays. The CKM picture provides very precise SM predictions through global analyses.
We present here the results of the latest global SM analysis performed...
Rare radiative-and-leptonic $B_s$-meson decay is a golden channel to scrutinize hypothetical New Physics (NP) effects in $b \to s$ quark transitions. Contrarily to the purely leptonic counterpart, i.e. $B_s \to \mu^+ \mu^-$, it is sensitive to a larger set of Wilson coefficients and it is not helicity suppressed. The LHCb Collaboration has set a first limit on the Branching Ratio (BR) of...
The photoleptonic decay Bโlฮฝฮณ* is the simplest low-energy process that probes the substructure of the B meson. For an energetic photon, its amplitude can be accessed within the frame of collinear factorization or QCD factorization (QCDF). The factorization formula depends critically on the light-cone distribution amplitudes (LCDAs) of the B meson. The physical photoleptonic amplitude arises in...
Radiative rare b-hadron decays offer a unique window into potential contributions from physics beyond the Standard Model through precise measurements of branching fractions, angular distributions, CP-violating observables, and photon polarization. The LHCb experiment, with its high-efficiency trigger system, excellent tracking resolution, and advanced particle identification capabilities,...
In this talk I will focus on the study of the leptonic $B\rightarrow \ell \nu$ decay at next-to-leading order in QED. The future improvements of experimental measurements of this channel require a reliable theory prediction, hence a careful theoretical estimate of QED corrections. The multi-scale character of this process requires an appropriate effective theory (EFT) construction to factorize...
We derive and solve the renormalization-group (RG) equation for the shape function $ g_{17}(\omega,\omega_1;\mu) $, which appears at subleading power in the factorization of the inclusive decays $ \bar{B} \to X_s \gamma $ and $ \bar{B} \to X_s \ell^+ \ell^- $.
Our results provide the first key ingredient for a next-to-leading order analysis of the resolved-photon $ Q_1^c - Q_{7\gamma} $...
An axion-like particle $a$ (ALP) can explain the excess of $B\rightarrow K+invisible$ events at Belle-II. However, many analyses of ALP scenarios are over-simplified. We revisit the $B\rightarrow K+a$ transition rate in a popular minimal and UV complete model with two Higgs doublets (2HDM) and a complex singlet (DFSZ model). To this end we compare our results with previous studies which...
