Search

Urgent theoretical progress is needed in order to provide an estimate in the Standard Model of the recent measurement by LHCb of direct CP violation in charm-meson two-body decays. Rescattering effects must be taken into account for a meaningful theoretical description of the amplitudes involved in such category of observables, as signaled by the presence of large strong phases. We discuss the computation of the latter effects based on a two-channel coupled dispersion relation, which exploits isospin-zero phase shifts and inelasticity parameterizations of data coming from the rescattering processes ππ→ππ, πK→πK, and ππ→KK¯. The determination of the subtraction constants of the dispersive integrals relies on the leading contributions to the transition amplitudes from the 1∕NC counting, where NC is the number of QCD colors. Furthermore, we use the measured values of the branching ratios to help in selecting the non-perturbative inputs in the isospin limit, from which we predict values for the CP asymmetries. We find that the predicted level of CP violation is much below the experimental value. [ABSTRACT FROM AUTHOR]

We have developed the covariant approach for the partial wave analysis of the radiative decay of the vector meson into two pseudoscalar mesons based on the orbital momentum- intrinsic spin decomposition. This allowed us to include the data on the radiative decay into a large data base for analysis of the meson production reactions. The correspondence between partial wave amplitudes extracted in our approach and those extracted in the helicity basis is determined. [ABSTRACT FROM AUTHOR]

The decays of the B meson into vector mesons, observed during the LHCb experiment, provide an ideal laboratory to investigate particle physics phenomena with quantum information theory methods. In this article, we focus on the decays yielding a pair of ϕ mesons to investigate the presence of entanglement in the spin correlations of the system and quantify the amount of Bell inequality violation it entails. Our results show that the present LHCb data allow access to entanglement and to the Bell inequality violation with a significance exceeding the 5 σ threshold in both the cases. This demonstrates that the strong and electroweak interactions responsible for the B meson decay act as a source of entanglement and the quantum mechanics nature of high-energy phenomena. Particular attention is paid to the assessment of loopholes: deficiencies in the experimental setup which could invalidate the results of the Bell test. [ABSTRACT FROM AUTHOR]

In recent years, it has been reported that rare charm decays have immense potential to probe physics beyond the standard model (SM). The Glashow–Iliopoulos–Maiani mechanism effectively suppresses the flavor changing neutral currents decays involving c → u transitions which makes them sensitive to new physics (NP) effects. In this work, we study D meson decays undergoing c → u l + l − transitions in nonuniversal Z ′ model. We determine the NP coupling from D 0 − D 0 ̄ mixing and D → μ + μ − process. We then estimate the upper limits of branching fractions and forward–backward asymmetries for the decays D → π μ + μ − , D s → K μ + μ − and D → ρ μ + μ − . The upper limits of the branching fractions obtained in the Z ′ model show a significant enhancement from their SM results. [ABSTRACT FROM AUTHOR]

Motivated by the study of heavy–light meson production within the framework of heavy quark effective theory (HQET) factorization, we extend the factorization formalism for a rather complicated process W + → B +ℓ+ℓ− in the limit of a nonzero invariant squared mass of the dilepton, q 2, at the lowest order in 1/ mb up to |$\mathcal {O}(\alpha _s)$|⁠. The purpose of the current study is to extend the HQET factorization formula for the W + → B +ℓ+ℓ− process and subsequently compute the form factors for this channel up to next-to-leading-order corrections in α s . We explicitly show that the amplitude of the W + → B +ℓ+ℓ− process can also be factorized into a convolution between the perturbatively calculable hard-scattering kernel and the nonperturbative yet universal light-cone distribution amplitude (LCDA) defined in HQET. The validity of the HQET factorization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. Within the HQET framework, we evaluate the form factors associated with the W + → B +ℓ+ℓ− process, providing insights into its phenomenology. In addition, we also perform an exploratory phenomenological study on W + → B +ℓ+ℓ− by employing an exponential model for the LCDAs for the B + meson. Our findings reveal that the branching ratio for W + → B +ℓ+ℓ− is below 10−10. Although the branching ratios are small, this channel in high-luminosity LHC experiments may serve to further constrain the value of λ B . [ABSTRACT FROM AUTHOR]

We present our first set of results for charm physics, using the mixed-action setup introduced in a companion paper [1]. Maximally twisted Wilson valence fermions are used on a sea of non-perturbatively O(a)-improved Wilson fermions, made up by CLS N f = 2 + 1 ensembles. Our charm-sector observables are free from O (a m c) discretisation effects, without need of tuning any improvement coefficient, and show continuum-limit scaling properties consistent with leading cutoff effects of O (a 2) . We consider a subset of CLS ensembles – including four values of the lattice spacing and pion masses down to 200 MeV – allowing to take the continuum limit and extrapolate to the physical pion mass. A number of techniques are incorporated in the analysis in order to estimate the systematic uncertainties of our results for the charm quark mass and the D (s) -meson decay constants. This first study of observables in the charm sector, where the emphasis has been on the control of the methodology, demonstrates the potential of our setup to achieve high-precision results. [ABSTRACT FROM AUTHOR]

The two-body leptonic decays of both light and heavy-charged mesons X l 2 ± are investigated in the first Born approximation in the presence of a monochromatic and circularly polarized laser field. As a result of using Volkov functions, the analytic study of these processes has brought a change in the parameters associated with each decay process. The decay width, lifetime, and branching ratio of each decay process are affected by increasing the classical parameter ξ of the meson. A comparison between the matter decay X l 2 + and that of the anti-matter X l 2 - in the presence of a circularly polarized laser wave, indicates that increasing laser field strength (increasing the classical parameter ξ ) can induce a slight dominance of matter over antimatter or vise versa. [ABSTRACT FROM AUTHOR]

The MoEDAL's Apparatus for Penetrating Particles (MAPP) Experiment is designed to expand the search for new physics at the LHC, significantly extending the physics program of the baseline MoEDAL Experiment. The Phase-1 MAPP detector (MAPP-1) is currently undergoing installation at the LHC's UA83 gallery adjacent to the LHCb/MoEDAL region at Interaction Point 8 and will begin data-taking in early 2024. The focus of the MAPP experiment is on the quest for new feebly interacting particles — avatars of new physics with extremely small Standard Model couplings, such as minicharged particles (mCPs). In this study, we present the results of a comprehensive analysis of MAPP-1's sensitivity to mCPs arising in the canonical model involving the kinetic mixing of a massless dark U(1) gauge field with the Standard Model hypercharge gauge field. We focus on several dominant production mechanisms of mCPs at the LHC across the mass-mixing parameter space of interest to MAPP: Drell-Yan pair production, direct decays of heavy quarkonia and light vector mesons, and single Dalitz decays of pseudoscalar mesons. The 95% confidence level background-free sensitivity of MAPP-1 for mCPs produced at the LHC's Run 3 and the HL-LHC through these mechanisms, along with projected constraints on the minicharged strongly interacting dark matter window, are reported. Our results indicate that MAPP-1 exhibits sensitivity to sizable regions of unconstrained parameter space and can probe effective charges as low as 8 × 10−4e and 6 × 10−4e for Run 3 and the HL-LHC, respectively. [ABSTRACT FROM AUTHOR]

We review recent developments in charm physics, focusing on the physics of charmed mesons. We discuss recent progress in charm spectroscopy and the multitude of mesonic and baryonic exotic states containing charm quarks. We review searches for new physics with charmed mesons with rare decays. We also touch upon recent theoretical and experimental progress in searches for CP-violation in charm decays and the status of D 0 - D ¯ 0 mixing. [ABSTRACT FROM AUTHOR]

We review the current status and implications of the anomalies (i.e. deviations from the Standard Model predictions) in semi-leptonic B meson decays, both in the charged and in the neutral current. In b → s ℓ + ℓ - transitions significant tensions between measurements and the Standard Model predictions exist. They are most pronounced in the branching ratios B B → K μ + μ - and B B s → ϕ μ + μ - (albeit quite dependent on the form factors used) as well as in angular observables in B → K ∗ μ + μ - (the P 5 ′ anomaly). Because the measurements of B B s → μ + μ - and of the ratios R(K) and R (K ∗) agree reasonably well with the SM predictions, this points towards (dominantly) lepton flavour universal NP coupling vectorially to leptons, i.e. contributions to C 9 U . In fact, global fits prefer this scenario over the SM hypothesis by 5.8 σ . Concerning b → c τ ν transitions, R(D) and R (D ∗) suggest constructive new physics at the level of 10 % (w.r.t. the Standard Model amplitude) with a significance above 3 σ . We discuss new physics explanations of both anomalies separately as well as possible combined explanations. In particular, a left-handed vector current solution to R (D (∗)) , either via the U 1 leptoquark or the combination of the scalar leptoquarks S 1 and S 3 , leads to an effect in C 9 U via an off-shell penguin with the right sign and magnitude and a combined significance (including a tree-level effect resulting in C 9 μ = - C 10 μ and R (D (∗)) ) of 6.3 σ . Such a scenario can be tested with b → s τ + τ - decays. Finally, we point out an interesting possible correlation of R (D (∗)) with non-leptonic B anomalies. [ABSTRACT FROM AUTHOR]

We discuss the main issues in dealing with heavy quarks on the lattice and shortly present the different approaches used. We discuss a selection of computations covering first the b-quark mass and the B (s) meson decay constants as the consolidated results (neglecting isospin breaking corrections). In the second part, we consider recent calculations of form factors for tree-level semileptonic decays with emphasis on the tensions between the results produced by different collaborations. We propose benchmark quantities and tests suited to investigate the origin of such tensions. Finally, we review computations of the bag parameters parameterising neutral meson mixing and provide an overview on a few recent developments in the field. [ABSTRACT FROM AUTHOR]

This article is based on the study of pure leptonic decays of charged pseudoscalar mesons taking nonuniversality into account. We calculate the branching ratios of the processes π ±, K±, D±, Ds±, b±. For the search for new physics (NP), we examine the discrepancies between theoretical and experimental results. The discrepancies are possibly due to massive neutrinos, processed massless in the Standard Model (SM), and universal coupling of leptons. We focus on the non-universality of leptons in order to find the bounds on Non-Standard Interaction (NSI) parameters ε. We use charge current like NSI and conclude that these decays could provide strong constraints on the NSI parameter. [ABSTRACT FROM AUTHOR]

The η (′) -mesons in the quark-flavor basis are mixtures of two mesonic states | η q ⟩ = | u ¯ u + d ¯ d ⟩ / 2 and | η s ⟩ = | s ¯ s ⟩. In previous work, we have made a detailed study on the η s leading-twist distribution amplitude by using the D s + meson semileptonic decays. As a sequential work, in the present paper, we fix the η q leading-twist distribution amplitude by using the light-cone harmonic oscillator model for its wave function and by using the QCD sum rules within the QCD background field to calculate its moments. The input parameters of η q leading-twist distribution amplitude ϕ 2 ; η q at the initial scale μ 0 ∼ 1 GeV are fixed by using those moments. The QCD sum rules for the 0 th -order moment can also be used to fix the magnitude of η q decay constant, giving f η q = 0.141 ± 0.005 GeV. As an application of ϕ 2 ; η q , we calculate the transition form factors B (D) + → η (′) by using the QCD light-cone sum rules up to twist-4 accuracy and by including the next-to-leading order QCD corrections to the leading-twist part, and then fix the related CKM matrix element and the decay width for the semi-leptonic decays B (D) + → η (′) ℓ + ν ℓ. [ABSTRACT FROM AUTHOR]

We propose a model-independent framework for fitting hadronic form-factor data, which is often only available at discrete kinematical points, using parameterisations based on to unitarity and analyticity. In this novel approach the latter two properties of quantum-field theory regulate the ill-posed fitting problem and allow model-independent predictions over the entire physical range. Kinematical constraints, for example for the vector and scalar form factors in semileptonic meson decays, can be imposed exactly. The core formulae are straight-forward to implement with standard math libraries. We take account of a generalisation of the original Boyd Grinstein Lebed (BGL) unitarity constraint for form factors and demonstrate our method for the exclusive semileptonic decay Bs→ Kℓν, for which we make a number of phenomenologically relevant predictions, including the CKM matrix element |Vub|. [ABSTRACT FROM AUTHOR]

The detection of radially excited charmonium and charm meson states, and measurement of heavy meson decays, particularly B c + → J / ψ D s + and B c + → J / ψ D s ∗ + , by the LHCb and ATLAS Collaborations, have aroused a lot of theoretical interest in the nonleptonic decays of b-flavored mesons. In this paper, we study the exclusive two-body nonleptonic B ¯ 0 , B s 0 ¯ , B - and B c - -meson decays to two vector meson ( V 1 (n S) V 2 ) states. Assuming the factorization hypothesis, we calculate the weak-decay form factors from the overlapping integrals of meson wave functions, in the framework of the relativistic independent quark (RIQ) model. We find a few dominant decay modes: B - → D ∗ 0 ρ - , B 0 ¯ → D ∗ + ρ - , B s 0 ¯ → D s ∗ + ρ - , B - → J / ψ K ∗ - and B c - → J / ψ D s ∗ - with predicted branching fractions of 1.52, 1.40, 1.16, 0.46 and 0.27 (in % ), which are experimentally accessible. The predicted branching fractions for corresponding decay modes to excited (2S) states, obtained in O (10 - 3 - 10 - 4) lie within the detection accuracy of the current experiments at LHCb and Tevatron. Our predicted CP-odd fractions ( R ⊥ ) for color-favored B c -decays to two charmful states ( D ∗ D (s) ∗ ) are found significant as compared to similar decay modes of other b-flavored mesons. [ABSTRACT FROM AUTHOR]

We calculate the next-to-leading order QCD corrections to B to scalar meson form factors from QCD light-cone sum rules with B meson light-cone distribution amplitudes. We demonstrate that the B meson-to-vacuum correlation functions can be factorized into the convolution of short-distance coefficients and light-cone distribution amplitudes at the one-loop level and find that only ϕ B + (ω, μ) contributes to the form factors. We then employ the z-parameterization combined with constraints from strong coupling constants to reconstruct the q2 dependence of the form factors in the whole kinematic allowed regions. Due to the large cancellations between the hard functions and the jet functions, the next-to-leading order results show a modest increase of approximately 5% compared to the leading order results. Based on the results of form factors, we predict the branching ratios of semi-leptonic B → S ℓ ν ¯ ℓ and B → S ν ℓ ν ¯ ℓ processes, as well as several angular observables, such as forward-backward asymmetries, "flat terms" and lepton polarization asymmetries. We compare these results with calculations from other methods. Experimental verification of these results is required in future experiments. [ABSTRACT FROM AUTHOR]

The T2K experiment is one of the most powerful long-baseline experiments to investigate neutrino oscillations. The off-axis near detector called ND280 is installed 280 m downstream from the neutrino production target to measure the neutrino energy spectrum. In this paper, we study the capability of the ND280 detector to search for the dark photon produced through the meson rare decay and proton bremsstrahlung processes at the proton beam dump. We find that the ten-year operation of T2K with the ND280 detector excludes the unexplored parameter region for the dark photon mass and kinetic mixing. We also show that a broader parameter region can be searched by the ND280 in the future T2K operation for dark photon as well as U(1)B−L gauge boson. [ABSTRACT FROM AUTHOR]

The principle optical scheme of the channel for the simultaneous formation of neutrino and antineutrino beams on the basis of the accelerator complex U-70 is considered. The main estimated characteristics of neutrino beams in the far detector at a distance of 2595 km from the end of the decay region of the channel, as well as the parameters of the parent mesons at the beginning of the decay region are discussed. The calculation scheme was used where the sources of muon neutrinos and antineutrinos are only the decays of mesons. [ABSTRACT FROM AUTHOR]

The B-L symmetric SUSY model (B-LSSM) introduces a new Z ′ gauge boson and two singlet scalars, which indicates there are more neutralinos in the B-LSSM comparing with the minimal SUSY extension of standard model (MSSM). These new neutralinos provide more dark matter (DM) candidates in the B-LSSM, we find that the super partner of the new scalar singlet can serve as the lightest supersymmetric particle (LSP) and be considered as a DM candidate. The properties of this new DM candidate are analyzed in this work. Taking into account the experimental constraints on Higgs boson mass, B meson rare decays and muon anomalous magnetic dipole moment, the numerical results are obtained and presented. The properties of new DM candidate in the B-LSSM satisfy the observed relic density Ω h 2 and comply with the latest upper bounds on σ SI χ 1 0 - n , and its mass is expected to greater than 80 GeV approximately. [ABSTRACT FROM AUTHOR]

In recent times, there have been several observations suggesting deviations from lepton universality in semileptonic decays of B mesons. These deviations have been noticed both in the neutral-current transitions (b → s l l) and charged-current transitions (b → c l ν ̄ l ). Motivated by these intriguing findings, we investigate the semileptonic decays involving the quark-level transitions of b → c l ν ̄ l . To explore the presence of new physics, we adopt a model-independent approach and analyze the processes Λ b → Λ c τ ν ̄ τ , B c + → η c τ + ν τ and B → D ∗ ∗ τ ν ̄ τ , where D ∗ ∗ = D 0 ∗ , D 1 ∗ , D 1 , D 2 ∗ represent the four lightest excited charm mesons. Considering a comprehensive effective Hamiltonian, we perform a global fit using various sets of new coefficients and incorporate measurements of R D , R D ∗ , R J ∕ ψ , P τ D ∗ , as well as the upper limit on the branching ratio of B c + → τ + ν τ . Subsequently, we examine the impact of constrained new couplings on the branching ratios, forward–backward asymmetry parameters, lepton nonuniversality (LNU) ratios, as well as lepton and hadron polarization asymmetries in these decay modes. [ABSTRACT FROM AUTHOR]

Motivated by a dynamical enhancement of the electromagnetic corrections by a power of ΛQCD/mb in Bd,s→ μ+μ− at next-to-leading order (NLO), we extend the QED factorization effects on the leptonic B meson decays with light muon leptons to tauonic final states, Bd,s→ τ+τ−, using soft-collinear effective theory (SCET). This extension is necessary owing to the appearance of the large τ mass, which will lead to different power counting in SCET and also different results. We provide a complete NLO electromagnetic corrections to Bd,s→ τ+τ−, which include hard functions and hard-collinear functions below the bottom quark mass scale μb. The power enhanced electromagnetic effects from hard-collinear contributions on Bd,s→ μ+μ− discussed before also exist in Bd,s→ τ+τ−. However the logarithm term arising from contributions of hard-collinear photon and lepton virtualities for Bd,s→ τ+τ− is not large as it is in muon case due to the hard-collinear scale of τ mass, which lead to only approximately 0.04% QED corrections to the branching fraction of Bd,s→ τ+τ− compared with overall reduction about 0.5% in Bd,s→ μ+μ−. [ABSTRACT FROM AUTHOR]

Recent results from the proton–proton collision data taken by the ATLAS experiment on the meson production and decays are presented. New results on the meson decays to or final states are included. This study is based on collision data collected at TeV during the LHC Run 2, corresponding to an integrated luminosity of 139 fb . The measurement of the ratios of the and meson differential production cross sections at TeV with an integrated luminosity of 20.3 fb is also discussed. [ABSTRACT FROM AUTHOR]

The rare decays, K+→π+νν¯, B+→π+νν¯ and D+→π+νν¯, are investigated in the frame work of nonstandard neutrino interactions (NSI). It is claimed that NSI are arising due to non-universality of the leptons and bounds on NSI parameters ϵll‧uL are determined. For this purpose, the branching ratios (Br) of these processes with in the Standard Model (SM) and beyond the SM are calculated by applying the non-universality of the leptons. The NSI in K+→π+νν¯ and B+→π+νν¯ proceed with u quark in the loop while other two with d quark in the loop. Very stringent 1 σ level constrains on non-standard parameters (ϵττuL and ϵτl‧uL) are pointed out. [ABSTRACT FROM AUTHOR]

The radiative B to tensor K 2 * (1430) , f 2 (1270) , a 2 (1320) meson decays are studied at next-to-leading order in soft-collinear effective theory (SCET). The SCET allows the systematic treatment of factorizable and non-factorizable contributions along with the resummation of large perturbative logarithms. We performed a two-step matching and determined the soft-overlap function ζ T ⊥ and branching ratios for these B to tensor meson decays. In the case of B → K 2 * (1430) γ , the numerical value of the branching ratio lies close to its experimental measurements. The estimated values of the branching ratios of Cabibbo–Kobayashi–Maskawa suppressed decays B → a 2 (1320) , f 2 (1270) γ are significantly small compared to that of B → K 2 * (1430) γ , but still could be measured in some ongoing and future B physics experiments. [ABSTRACT FROM AUTHOR]

Motivated by a dynamical enhancement of the electromagnetic corrections by a power of ΛQCD/mb in Bd,s→ μ+μ− at next-to-leading order (NLO), we extend the QED factorization effects on the leptonic B meson decays with light muon leptons to tauonic final states, Bd,s→ τ+τ−, using soft-collinear effective theory (SCET). This extension is necessary owing to the appearance of the large τ mass, which will lead to different power counting in SCET and also different results. We provide a complete NLO electromagnetic corrections to Bd,s→ τ+τ−, which include hard functions and hard-collinear functions below the bottom quark mass scale μb. The power enhanced electromagnetic effects from hard-collinear contributions on Bd,s→ μ+μ− discussed before also exist in Bd,s→ τ+τ−. However the logarithm term arising from contributions of hard-collinear photon and lepton virtualities for Bd,s→ τ+τ− is not large as it is in muon case due to the hard-collinear scale of τ mass, which lead to only approximately 0.04% QED corrections to the branching fraction of Bd,s→ τ+τ− compared with overall reduction about 0.5% in Bd,s→ μ+μ−. [ABSTRACT FROM AUTHOR]

We study the current estimates of B c → B s π to extract the fragmentation fraction f c / f s at the LHCb. A rather robust estimate of B r (B c → B s π) based on factorization and lattice results for the form factor gives f c / f s ∼ 0.056 with a 16% error. We also revisit the extraction of f s / f d using B → D π instead of the theoretical cleaner but more suppressed channel B → D K . We also find a tension on the predictions of B r (B c → J / ψ π) and B r (B c → B s π) considering the measurements of these modes at LHCb, and find that, within a 23% uncertainty, only the lower end of the current prediction range B r (B c → J / ψ) ∼ 0.4 % - 1.7 % would be consistent with the LHCb measurements. [ABSTRACT FROM AUTHOR]

Atmospheric muon neutrinos are produced by meson decays in cosmic-ray-induced air showers. The flux depends on meteorological quantities such as the air temperature, which affects the density of air. Competition between decay and re-interaction of those mesons in the first particle production generations gives rise to a higher neutrino flux when the air density in the stratosphere is lower, corresponding to a higher temperature. A measurement of a temperature dependence of the atmospheric ν μ flux provides a novel method for constraining hadronic interaction models of air showers. It is particularly sensitive to the production of kaons. Studying this temperature dependence for the first time requires a large sample of high-energy neutrinos as well as a detailed understanding of atmospheric properties. We report the significant ( > 10 σ ) observation of a correlation between the rate of more than 260,000 neutrinos, detected by IceCube between 2012 and 2018, and atmospheric temperatures of the stratosphere, measured by the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's AQUA satellite. For the observed 10 % seasonal change of effective atmospheric temperature we measure a 3.5(3) % change in the muon neutrino flux. This observed correlation deviates by about 2-3 standard deviations from the expected correlation of 4.3 % as obtained from theoretical predictions under the assumption of various hadronic interaction models. [ABSTRACT FROM AUTHOR]

We investigate the weak leptonic and semileptonic decay widths of pseudoscalar light and heavy mesons in a Dirac formalism. We take relativistic-independent quark model of the form V q (r) = 1 2 (1 + γ 0) (a 2 r + V 0) , where a > 0. This is computed using the binding quark eigenfunction and taking the assumptions of a significant relationship between the quark and antiquark momenta inside the decaying meson in the rest frame. To calculate the decay constant (f M) , decay width and branching fractions of pseudoscalar mesons, we employ the model parameters that we used earlier. The experimental findings and various similar models are in good agreement with our predictions such as " f B C > f B S > f B , f D S > f D , f D > f B and f B > f π ". Finally, we calculate the form factors and branching fractions for the semileptonic D (D 0) decays " D + → K S 0 e + ν e ,  D + → K L 0 e + ν e ,  D + → π 0 e + ν e ,  D 0 → K − e + ν e and D 0 → π − e + ν e " and find reasonable agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The aim of this text is to present the covariant confined quark model (CCQM) and review its applications in the decays of B mesons. We do so in the context of existing experimental measurements and theoretical results of other authors, which we also review. The physics principles are, in detail, exposed for the CCQM; the other results (theoretical and experimental) are surveyed in an enumerative way with comments. We proceed by considering, successively, three categories of decay processes: leptonic, semileptonic and non-leptonic. [ABSTRACT FROM AUTHOR]

The decay B 0 → D ∗ + D - is favorable mode for studying CP violation in the interference between mixing and decay for B 0 and B ¯ 0 mesons. The latest analysis of the CP parameters has been performed by the LHCb Collaboration values of S D ∗ D = - 0.861 ± 0.077 ± 0.019 , C D ∗ D = - 0.059 ± 0.092 ± 0.020 , ▵ S D ∗ D = 0.019 ± 0.075 ± 0.012 , ▵ C D ∗ D = - 0.031 ± 0.092 ± 0.016 , and A D ∗ D CP = 0.008 ± 0.014 ± 0.006 ± 0.003 . We have been estimated the parameters S D ∗ D and C D ∗ D of the B 0 → D ∗ + D - decay as - 0.709 ± 0.024 and - 0.051 ± 0.004 . In the following, we have obtained the values of ▵ S D ∗ D = 0.054 ± 0.003 and ▵ C D ∗ D = 0.020 ± 0.001 and direct CP violation of 0.008 ± 0.001 . Also, we have calculated the branching ratio of B 0 → D ∗ + D - decay. The values obtained in this work are comparable with the corresponding experimental values. [ABSTRACT FROM AUTHOR]

I describe the history of the calculations of NLO and NNLO QCD corrections to weak decays of mesons, particle–antiparticle mixing and electric dipole moments (EDMs) in the period 1988–2023. Also existing calculations of electroweak and QED corrections to these processes are included in this presentation. These efforts bear some analogies to the climbing of Himalayas and various expeditions by several teams of strongly motivated "climbers" allowed to move this field from the LO through the NLO to the NNLO level. We also summarize the most recent calculations within the Standard Model Effective Field Theory. The material is meant to be an up to date review of this very advanced field in non-technical terms as much as possible and a guide to the rich literature on NLO and NNLO corrections in question. In particular we stress for which processes these calculations are crucial for the tests of the Standard Model and to be able to differentiate between numerous New Physics models. It includes also several anecdotes related to the climbs that I was involved in. I hope that some of the comments made in the course of the presentation could turn out to be not only amusing but also instructive. [ABSTRACT FROM AUTHOR]

In this work, we investigate the resonant contributions of K 0 ∗ 1430 and K 0 ∗ 1950 in the three-body B s ⟶ D s K π within the perturbative QCD approach. The form factor F k π s is adopted to describe the nonperturbative dynamics of the S-wave K π system. The branching ratios of all concerned decays are calculated and predicted to be in the order of 1 0 − 10 to 1 0 − 5 . The ratio R of branching fractions between B 0 ⟶ D ¯ 0 K 0 ∗ 0 1430 ⟶ D ¯ 0 K + π − and B s 0 ⟶ D ¯ 0 K ¯ 0 ∗ 0 1430 ⟶ D ¯ 0 K − π + is predicted to be 0.0552, which implies the discrepancy for the LHCb measurements. We expect that the predictions in this work can be tested by the future experiments, especially, to resolve R ratio discrepancy. [ABSTRACT FROM AUTHOR]

We review the current status of the long-term programme of numerical investigation of S p (2 N) gauge theories with and without fermionic matter content. We start by introducing the phenomenological as well as theoretical motivations for this research programme, which are related to composite Higgs models, models of partial top compositeness, dark matter models, and in general to the physics of strongly coupled theories and their approach to the large-N limit. We summarise the results of lattice studies conducted so far in the S p (2 N) Yang–Mills theories, measuring the string tension, the mass spectrum of glueballs and the topological susceptibility, and discuss their large-N extrapolation. We then focus our discussion on S p (4) , and summarise the numerical measurements of mass and decay constant of mesons in the theories with fermion matter in either the fundamental or the antisymmetric representation, first in the quenched approximation, and then with dynamical fermions. We finally discuss the case of dynamical fermions in mixed representations, and exotic composite fermion states such as the chimera baryons. We conclude by sketching the future stages of the programme. We also describe our approach to open access. [ABSTRACT FROM AUTHOR]

Many models beyond the Standard Model predict light and feebly interacting particles that are often long-lived. These long-lived particles (LLPs) in many cases can be produced from meson decays. In this work, we propose a simple and quick reinterpretation method for models predicting LLPs produced from meson decays. With the method, we are not required to run Monte-Carlo simulation, implement detector geometries and efficiencies, or apply experimental cuts in an event analysis, as typically done in recasting and reinterpretation works. The main ingredients our method requires are only the theoretical input, allowing for computation of the production and decay rates of the LLPs. There are two conditions for the method to work: firstly, the LLPs in the models considered should be produced from a set of mesons with similar mass and lifetime (or the same meson) and second, the LLPs should, in general, have a lab-frame decay length much larger than the distance between the interaction point and the detector. As an example, we use this method to reinterpret exclusion bounds on heavy neutral leptons (HNLs) in the minimal "3+1" scenario, into those for HNLs in the general effective-field-theory framework as well as for axion-like particles. We are able to reproduce existing results, and obtain new bounds via reinterpretation of past experimental results, in particular, from CHARM and Belle. [ABSTRACT FROM AUTHOR]

Searches for new low-mass matter and mediator particles have actively been pursued at fixed target experiments and at e+e− colliders. It is challenging at the CERN LHC, but they have been searched for in Higgs boson decays and in B meson decays by the ATLAS and CMS Collaborations, as well as in a low transverse momentum phenomena from forward scattering processes (e.g., FASER). We propose a search for a new scalar particle in association with a heavy vector-like quark. We consider the scenario in which the top quark (t) couples to a light scalar ϕ′ and a heavy vector-like top quark T. We examine single and pair production of T in pp collisions, resulting in a final state with a top quark that decays purely hadronically, a T which decays semileptonically (T → W + b → ℓ ν b), and a ϕ′ that is very boosted and decays to a pair of collimated photons which can be identified as a merged photon system. The proposed search is expected to achieve a discovery reach with signal significance greater than 5σ (3σ) for m(T) as large as 1.8 (2) TeV and m(ϕ′) as small as 1 MeV, assuming an integrated luminosity of 3000 fb−1. This search can expand the reach of T, and demonstrates that the LHC can probe low-mass, MeV-scale particles. [ABSTRACT FROM AUTHOR]

We study flavor changing neutral current decays of B and K mesons in the dark U(1)D model, with the dark photon/dark Z mass between 10 MeV and 2 GeV. Although the model provides an improved fit (compared to the standard model) to the differential decay distributions of B → K(∗)ℓ+ℓ−, with ℓ = μ, e, and Bs→ ϕμ+μ−, the allowed parameter space is ruled out by measurements of atomic parity violation, K+→ μ+ + invisible decay, and B s − B ¯ s mixing, among others. To evade constraints from low energy data, we extend the model to allow for (1) additional invisible ZD decay, (2) a direct vector coupling of ZD to muons, and (3) a direct coupling of ZD to both muons and electrons, with the electron coupling fine-tuned to cancel the ZD coupling to electrons via mixing. We find that only the latter case survives all constraints. [ABSTRACT FROM AUTHOR]

We consider decays of B and K mesons into a pseudo-scalar or vector meson plus missing energy. Within the SM, these modes originate from flavor changing neutral current (FCNC) processes with two neutrinos in the final state. In this paper we consider the experimental upper bounds on these modes and interpret the difference between these bounds and the SM prediction as a window into new light invisible particles. In particular we consider the case where some new symmetry requires the new particles to be produced in pairs. We first construct the general low energy effective Lagrangian coupling an FCNC with two dark sector particles of spin zero, one-half and one. We then present numerical estimates for the constraints that can be placed on these interactions, finding that an effective new physics scale from O (10)- O (1011) GeV can be probed, with the exact value strongly depending on the interaction structure as well as the mass of the invisible particle. For we incorporate into our constraints the effect of using only the signal regions of NA62, and for the q2-dependent efficiency of Belle II. [ABSTRACT FROM AUTHOR]

The future Electron-Ion Collider (EIC) at Brookhaven National Laboratory, along with its primary capacity to elucidate the nuclear structure, will offer new opportunities to probe physics beyond the Standard Model coupled to the electroweak sector. Among the best motivated examples of such new physics are new heavy neutral leptons (HNLs), which are likely to play a key role in neutrino mass generation and lepton number violation. We study the capability of the EIC to search for HNLs, which can be produced in electron- proton collisions through charged current interactions as a consequence of their mixing with light neutrinos. We find that, with the EIC design energy and integrated luminosity, one is able to probe HNLs in the mass range of 1 – 100 GeV with mixing angles down to the order of 10−4 − 10−3 through the prompt decay signatures, and in the mass range of 1 10 GeV with |Ue|2 ~ 10−6 – 10−4 via the displaced decay signatures. We also consider the invisible mode where an HNL is undetected or decaying to dark sector particles. One could potentially probe heavy HNLs for mixing angles in the window 10−3 – 10−2, provided SM background systematics can be brought under control. These searches are complementary to other probes of HNLs, such as neutrino-less double-β decay, meson decay, fixed-target, and high-energy collider experiments. [ABSTRACT FROM AUTHOR]

Axion–Like–Particles are among the most economical and well motivated extensions of the Standard Model. In this work ALP production from hadronic and leptonic meson decays are studied. The hadronization part of these decay amplitudes have been obtained using Brodsky–Lepage method or LQCD, at needs. In particular, the general expressions for ALP emission in mesonic s– and t–channel tree–level processes are thoroughly discussed, for pseudoscalar and vector mesons. Accordingly, the calculation of the decay amplitudes for MI→MFa$M_I\rightarrow M_F \,a$ and M→ℓνa$M\rightarrow \ell \nu a$ are presented. Finally, bounds on the (low–energy effective Lagrangian) ALP–fermion couplings are derived, from present and future flavor experiments. Axion–Like–Particles are among the most economical and well motivated extensions of the Standard Model. In this work ALP production from hadronic and leptonic meson decays are studied. The hadronization part of these decay amplitudes have been obtained using Brodsky–Lepage method or LQCD, at needs. In particular, the general expressions for ALP emission in mesonic s– and t–channel tree–level processes are thoroughly discussed, for pseudoscalar and vector mesons. Accordingly, the calculation of the decay amplitudes for MI→MFa$M_I\rightarrow M_F \,a$ and M→ℓνa$M\rightarrow \ell \nu a$ are presented. Finally, bounds on the (low–energy effective Lagrangian) ALP–fermion couplings are derived from present and future flavor experiments. [ABSTRACT FROM AUTHOR]

ALICE-3 is being designed as a next-generation heavy-ion experiment to be operated at the high-luminosity Large Hadron Collider. With luminosities higher by a factor of fifty, ALICE-3 will be able to study5 properties of quark–gluon matter with probes and precision which were previously unavailable due to small cross sections, high background levels, and insufficient detector sensitivity. In particular, the properties of hot and dense QCD matter will be studied by measuring production cross sections, flow coefficients, azimuthal angular correlations and nuclear modification factors for open-charm hadrons. In this contribution, we present the results of feasibility studies for the measurement of ground and excited states of open-charm mesons in decay channels D0 → K− + π+ + π0, D*(2007)0 → D0 + γ and D*(2010)± → D0 + π± in pp, p-Pb and Pb-Pb collisions at LHC energies using the ALICE-3 experimental setup. We formulate the main requirements for the selection of particles and their combinations to ensure reliable signal extraction in a wide transverse momentum range and estimate the minimum size of the required data samples. The results obtained are also compared to previous findings for the open-charm measurements in different decay channels. [ABSTRACT FROM AUTHOR]

Laser-induced nuclear reactions in ultra-dense hydrogen H(0) (review in Physica Scripta 2019) create mesons (kaons and pions). These mesons decay mainly to muons. The muons created are useful (patented source) for the muon-induced fusion process. The sign of the muons from the source depends on the initial baryons used. With D(0) (ultra-dense deuterium) the source produces mainly positive muons and with p(0) (ultra-dense protium) the source produces mainly negative muons. Negative muons are required for muon-induced fusion. This charge asymmetry was reported earlier, and has now been confirmed by experiments with a coil current transformer as the beam detector. The current coil detector would give no signal from the muons if charge symmetry existed. The charge asymmetry could indicate unknown processes, for example, caused by the different annihilation processes in D(0) and p(0). The conclusions of a new analysis of the results are presented here. Using D(0) in the muon source, the asymmetry is likely due to the capture of µ- in D atoms and D2 molecules. This leads to emission of excess µ+ from D(0). With p(0) in the muon source, the capture rate of µ- is lower than in D(0). The emitted number of µ+ will be decreased by the reaction between µ+ and the surrounding abundant electrons, forming neutral muonium particles. This effect decreases the amount of emitted µ+ for both p(0) and D(0), and it is proposed to be the main reason for a larger fraction of emitted µ- in the case of p(0). Thus, there is no dominant emission of negative muons which would violate charge conservation. [ABSTRACT FROM AUTHOR]

Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the availability of very large datasets. On the other hand, useful complementary information is provided by hyperon decay measurements. We summarize the relevant phenomenological models and the status of the searches in a comprehensive list of kaon and hyperon decay channels. We identify new search strategies for under-explored signatures, and demonstrate that the improved sensitivities from current and next-generation experiments could lead to a qualitative leap in the exploration of light dark sectors. [ABSTRACT FROM AUTHOR]

It is shown that muons are generated from decay of the mesons created by baryon annihilation reactions in ultra-dense hydrogen H(0), based on numerous previous publications and one patent. The cost of the muons in energy is 500 times lower than from production in particle accelerators; therefore, they are considered to be cheap. We argue that ordinary scientific publications are more suitable for proving or disproving scientific results than comments with no new information. [ABSTRACT FROM AUTHOR]

Using proton-proton collision data, collected by the LHCb experiment and corresponding to the integrated luminosity of 9 fb−1, the several new decays to charmonium and three light charged hadrons are observed. In particular, following channels are observed → ψ(2S)π+π−π+, → (ψ(2S) → J/ψπ+π−)π+, → J/ψK+π−π+, and → J/ψK+K−K+. The first evidence of the → ψ(2S)K+K−π+ decays is obtained. The branching fractions of these decays are measured with respect to the high-statistic normalization channels. [ABSTRACT FROM AUTHOR]

Masses of the ground and excited (1P, 2S, 1D, 2P, 3S) states of the fully heavy tetraquarks, composed of charm (c) and bottom (b) quarks and antiquarks, are calculated in the diquark–antidiquark picture within the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The quasipotentials of the quark–quark and diquark–antidiquark interactions are constructed similarly to the previous consideration of mesons and baryons. Relativistic effects are consistently taken into account. A tetraquark is considered a bound state of a diquark and an antidiquark. The finite size of the diquark is taken into account, using the form factors of the diquark–gluon interaction. It is shown that most of the investigated states of tetraquarks lie above the decay thresholds into a meson pair; as a result, they can be observed only as broad resonances. The narrow state X(6900) recently discovered in the di- J / ψ production spectrum by the LHCb, CMS and ATLAS Collaborations corresponds to an excited state of the fully charmed tetraquark. Other recently discovered exotic heavy resonances, X(6200), X(6400), X(6600), X(7200), and X(7300), can also be interpreted as the different excitations of the fully charmed tetraquark. [ABSTRACT FROM AUTHOR]

A Peccei-Quinn (PQ) symmetry is proposed, in order to generate in the Standard Model (SM) quark sector a realistic mass matrix ansatz with five texture-zeros. Limiting our analysis to Hermitian mass matrices we show that this requires a minimum of 4 Higgs doublets. This model allows assigning values close to 1 for several Yukawa couplings, giving insight into the origin of the mass scales in the SM. Since the PQ charges are non-universal the model features Flavor-Changing Neutral Currents (FCNC) at the tree level. From the analytical expressions for the FCNC we report the allowed region in the parameter space obtained from the measurements of branching ratios of semileptonic meson decays. [ABSTRACT FROM AUTHOR]

The spectroscopic parameters of the heavy-light hybrid mesons with different spin-parities and different quark contents are investigated in the framework of the QCD sum rule method. The mass and current coupling of these states are calculated by taking into account the quark, gluon and mixed vacuum condensates up to dimension 10. The obtained results are compared with the existing QCD Laplace sum rule predictions. The results of mass and current coupling for all the considered channels are obtained to be stable and reliable. Our results can be useful for future experimental searches as well as theoretical studies of different parameters related to the hybrid mesons and their decays and interactions with other particles. [ABSTRACT FROM AUTHOR]

We extend the contents of the standard model (SM) by introducing TeV-scale scalar leptoquarks to generate neutrino masses and explain some current observed deviations from the SM predictions, including the anomalous magnetic moments of charged leptons (electron and muon) and B-physics anomalies ( R K (∗) and R D (∗) ). The model consists of SU (2) L singlet leptoquark S 1 ∼ (3 ¯ , 1 , 1 / 3) , doublet leptoquark R ~ 2 ∼ (3 , 2 , 1 / 6) and triplet leptoquark S 3 ∼ (3 ¯ , 3 , 1 / 3) . We combine the constraints arising from the low-energy lepton flavor violation, meson decay and mixing observables. We perform a detailed phenomenological analysis and identify the minimized texture of leptoquark Yukawa matrices to accommodate a unified explanation of the anomalies and neutrino oscillation data. [ABSTRACT FROM AUTHOR]

Using the 1.32 pb - 1 statistics collected at the J / ψ peak with the KEDR detector at the VEPP-4M e + e - collider, we measured the branching fractions of J / ψ meson decays to the final states 2( π + π -) π 0 , K + K - π + π - π 0 , 2( π + π -) and K + K - π + π - . The results obtained for the decays J / ψ → 2( π + π -) π 0 , J / ψ → K + K - π + π - π 0 contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations. [ABSTRACT FROM AUTHOR]

In light of recent measurements suggesting potential lepton flavor universality violations in semileptonic decays at collider experiments, this article provides a concise study of tree- and loop-level B-hadron semileptonic decays, b→clνl\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$b \rightarrow c l \nu _l$$\end{document} and b→sl+l-\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$b \rightarrow s l^+ l^-$$\end{document}. We provide predictions for lepton flavor violating observables, RJ/ψ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\mathcal {R}}_{J/\psi }$$\end{document} and Rηc\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\mathcal {R}}_{\eta _c}$$\end{document}, across the entire q2\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$q^2$$\end{document} range. Our study employs the Relativistic Independent Quark Model (RIQM), highlighting a model-dependent approach to these observables. We compare our model’s predictions with existing lattice predictions, demonstrating the strong applicability of the RIQM framework in describing Bc\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$B_c$$\end{document} decays. Additionally, we reassess global averages for RD(D∗)\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\mathcal {R}}_{D(D^*)}$$\end{document} and RK(K∗)\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\mathcal {R}}_{K(K^*)}$$\end{document} in semileptonic transitions. With the upcoming experimental upgrades and the anticipated Run 3 data on Bc\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$B_c$$\end{document} meson decays, rapid confirmation of these quantities could indicate significant evidence of physics beyond the Standard Model, thereby opening new pathways for understanding the complex flavor dynamics in B meson decays. [ABSTRACT FROM AUTHOR]