We perform a general SU(3)$_F$ analysis of $b\rightarrow c\bar{c}s(d)$ decays of members of the beauty baryon antitriplet to a member of the light baryon octet and a singlet. Under several reasonable assumptions we found $\left\vert \mathcal{A}(Ξ_b^0\rightarrow ΛS)/ \mathcal{A}(Ξ_b^0\rightarrow Ξ^0 S)\right\vert\approx 1/\sqrt{6}\, \left\vert V_{cb}^* V_{cd} / (V_{cb}^* V_{cs})\right\vert$ and $\left\vert\mathcal{A}(Λ_b\rightarrow Σ^0 S)/\mathcal{A}(Λ_b\rightarrow ΛS)\right\vert \sim 0.02$. These two relations have been recently probed by LHCb for the case of $S=J/ψ$. The former agrees with the measurement, while for the latter our prediction lies close to the upper bound set by LHCb.
We consider hadronic weak decays of beauty-baryons into charmless baryons and pseudoscalar mesons in a general framework based on $SU(3)$ decomposition of the decay amplitudes. The advantage of the approach lies in the ability to perform an $SU(3)$ analysis of these decays without any particular set of dynamical assumptions while accounting for the effects of an arbitrarily broken $SU(3)$ flavor symmetry. Dictated by the symmetries of the effective Hamiltonian that allow us to relate or neglect reduced $SU(3)$ amplitudes, we derive several sum rule relations between amplitudes and relations be…
Several baryons containing a heavy b-quark, the b-baryons, have been discovered. The charmless two-body decays of b-baryons can provide a new platform for CP violating studies in a similar way as charmless two-body decays of B-meson. In b-baryon decays there are new CP violating observable related to baryon polarization. We show that in the flavor $SU(3)$ limit there exist relations involve different combinations of the decay amplitudes compared with those in CP violating rate asymmetry. These new relations therefore provide interesting tests for the mechanism of CP in the standard model (SM) …
Beauty baryons are being observed in large numbers in the LHCb detector. The rich kinematic distributions of their multibody decays are therefore becoming accessible and provide us with new opportunities to search for CP violation. We analyse the angular distributions of some three- and four-body decays of spin-$1/2$ baryons using the Jacob-Wick helicity formalism. The asymmetries that provide access to small differences of CP-odd phases between decay amplitudes of identical CP-even phases are notably discussed. The understanding gained on processes featuring specific resonant intermediate sta…
The production of charmed and beauty baryons in proton-proton collisions at high energies is analyzed within the modified quark-gluon string model. We present some predictions for the experiments on the forward beauty baryon production in pp collisions at LHC energies. This analysis allows us to find useful information on the Regge trajectories of the heavy (b barb) mesons and the sea beauty quark distributions in the proton.
One of the outstanding problems in physics is to explain the baryon-anti-baryon asymmetry observed in nature. According to the well-known Sakharov criterion for explaining the observed asymmetry, it is essential that $CP$ violation exist. Even though $CP$ violation has been observed in meson decays and is an integral part of the standard model (SM), measurements in meson decays indicate that $CP$ violation in the SM is insufficient to explain the observed baryon-anti-baryon asymmetry. SM predicts the existence of yet to be observed $CP$ violation in baryon decays. A critical test of the SM req…
Possible mixing and its consequences of heavy cascade baryons Ξ-Ξ^\prime is analyzed and its importance in the analysis of their characteristics is shown within the non-relativistic quark model and QCD sum rules.
With a distinctive internal structure from all established hadrons, the beauty-charmed baryons $Ξ_{bc}$ can provide us with new points of view to decipher the strong interaction. In this work, we point out that the inclusive $Ξ_{bc} \to Ξ_{cc}^{++}+X$ decay is a golden channel for the experimental discovery of $Ξ_{bc}$ at the LHC. A unique feature of this process is that the $Ξ_{cc}^{++}$ is displaced, which greatly reduces the combinatorial background. A feasibility analysis is performed on the $Ξ_{bc}^+$ search, which is expected to have a longer lifetime than $Ξ_{bc}^0$ and thus a better di…
The production of charmed and beauty hadrons in proton-proton collisions at high energies are analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. We present some predictions for the future experiments on the beauty baryon production in $pp$ collisions at LHC energies. This analysis allows us to find interesting information on the Regge trajectories of the heavy (b{\bar b}) mesons and the sea beauty quark distributions in the proton.
We consider charmless weak decays of beauty-baryons into decuplet baryons and pseudoscalar mesons in a general framework based on $SU(3)$-flavor decomposition of the decay amplitudes. The dynamical assumption independent $SU(3)$ analysis accounts for the effects of an arbitrarily broken $SU(3)$ symmetry in these decays. An alternative approach in terms of quark diagrams is also provided and compared with the $SU(3)$ decomposition in the limit of exact $SU(3)$-flavor symmetry. Furthermore, the symmetries of the effective Hamiltonian is used to relate or neglect reduced $SU(3)$ amplitudes to der…
LHCb is a dedicated heavy flavour physics precision experiment at the LHC searching for New Physics (NP) beyond the Standard Model (SM) through the study of very rare decays of beauty and charm-flavoured hadrons and precision measurements of CP-violating observables. In this review I will present a selection of recent precision measurements of CP-violating observables in the decays of beauty and charm-flavoured hadrons. These measurements are based on an integrated luminosity of up to $1.0 \rm{fb}^{-1}$ collected by LHCb in 2011.
Tree-level $b$ decays play a critical role in characterising the quark flavour sector, and exposing possible effects of physics beyond the Standard Model. These proceedings cover recent results from the LHCb experiment on semileptonic $b$ baryon decays, $\mathcal{R}(D^{\ast-})$ using three-prong hadronic $τ$ decays, $CP$ observables in $B^- \to D^{(\ast)}h^-$ decays, and an updated combination on the CKM angle $γ$.
We briefly review the stability of the $QQ\bar q\bar q$-type of tetraquarks with two heavy quarks and two light antiquarks. We present the first comprehensive estimate of the lifetime and leading decay modes of the exotic meson $bb\bar u\bar d$ with double beauty.
A novel observable measuring the $C\!P$ asymmetry in multi-body decays of heavy mesons, which is called the forward-backward asymmetry induced $C\!P$ asymmetry (FBI-$C\!P$A), $A_{CP}^{FB}$, is introduced. This observable has the dual advantages that 1) it can isolate the $C\!P$ asymmetry associated with the interference of the $S$- and $P$-wave amplitude from that associated with the $S$- or $P$-wave amplitude alone; 2) it can effectively almost double the statistics comparing to the conventionally defined regional $C\!P$ asymmetry. We also suggest to perform the measurements of FBI-$C\!P$A in…
The recent discovery, by the LHCb collaboration, of the $Ξ_{cc}^{++}$ doubly charmed baryon, has renewed interest in the spectroscopy of doubly heavy hadrons. Experimentally, however, searches for such states appear highly challenging. The reconstructed final states tend to involve multiple heavy flavoured (beauty or charm) hadrons, so the yield for any exclusive decay mode will be suppressed to unobservably low levels by the product of several branching fractions, each of which is typically $10^{-3}$--$10^{-2}$. Noting that decays of double beauty hadrons are the only possible source of $B_c^…
We study baryon resonances with heavy flavor in a molecular approach, thus as dynamically generated by baryon-meson scattering. This is accomplished by using a unitary coupled-channel model taking, as bare interaction, the extension of the Weinberg-Tomozawa SU(3) Lagrangian. A special attention is payed to the inclusion of heavy-quark spin symmetry and to the study of the generated baryon resonances that complete the heavy-quark spin multiplets. Our model reproduces the Λ_b(5912) and Λ_b(5920) baryons, which were recently observed by the LHCb collaboration. According to our analysis, these two…
Rare flavour changing neutral current (FCNC) decays of top, beauty and charm quarks can provide a powerful probe for as yet unobserved particles. Recent results on FCNC $b \to s$, $c \to u$ and $t$ transitions from the LHC experiments are reviewed. Particular attention is paid to the angular distribution of the $B^{0} \to K^{*0} μ^{+} μ^{-}$ decay, where a measurement performed by LHCb shows a local discrepancy of 3.7 standard deviations with respect to the SM prediction. Using the decay $B^{+} \to K^{+}π^{-}π^{+}γ$, LHCb have also been able to demonstrate the polarisation of photons produced …
The meson-baryon coupled channel unitary approach with the local hidden gauge formalism is extended to the hidden beauty sector. A few narrow $N^*$ and $Λ^*$ resonances around 11 GeV are predicted as dynamically generated states from the interactions of heavy beauty mesons and baryons. Production cross sections of these predicted resonances in $pp$ and $ep$ collisions are estimated as a guide for the possible experimental search at relevant facilities.
Observation in astronomy suggests that our Universe contains an abundance of matter over antimatter, which can only be explained if the combined CP symmetry is violated. Studies of CP violation have driven the flavor physics with the aim of testing the Standard Model of particle physics and searching for physics beyond. CP violation is discovered in strange, beauty and charm meson systems, however no conclusive sign of CP violation in baryon decays has been observed yet. This review summarizes CP violation studies performed by the LHCb experiment in charmless decays and rare decays of beauty b…
We present the measurements, performed by the Belle II experiment, related to the B and D meson decays. These results are based on 63 fb$^{-1}$ and 9 fb$^{-1}$ of $e^+e^-$ collision data recorded by the Belle II detector at a center-of-mass energy corresponding to the mass of the Y(4S) resonance and 60 MeV below the Y(4S) resonance. The results reassure that Belle II is in the right direction in pursuit of measuring the Standard Model predictions with improved precision.
The role of rescaling (expansion or squeezing) of quantized skyrmions is studied for the spectrum of baryons beginning with nucleon and $Δ(1232)$, and with flavors strangeness, charm or beauty. The expansion of skyrmions due to the centrifugal forces has influence on the masses of baryons without flavor ($N$ and especially $Δ$). The rescaling of skyrmions has smaller influence on the spectrum of strange baryons, it is more important for the case of charm, and is crucial for baryons with beauty quantum number, where strong squeezing takes place. Two competing tendencies are clearly observed: ex…
Since the discovery of CP violation more than 5 decades ago, this phenomenon is still attracting a lot of interest. Among the many fascinating aspects of this subject, this review is dedicated to direct CP violation in non-leptonic decays. The advances within the last decade have been enormous, driven by the increasingly large samples of b- and c-hadron decays, and have led to very interesting results such as large CP asymmetries in charmless B decays and the observation of direct CP violation in the charm sector. We address the quest for understanding the origin of strong phases, the importan…
Several baryons containing a heavy b-quark have been discovered. The decays of these states provide new platform for testing the standard model (SM). We study $CP$ violation in SM for charmless two-body decays of the flavor $SU(3)$ anti-triplet beauty baryon (b-baryon) ${\cal B} = (Ξ^-_b,\;Ξ^0_b,\;Λ_b^0)$ in a model independent way. We found, in the flavor $SU(3)$ symmetry limit, a set of new predictive relations among the branching ratio $Br$ and $CP$ asymmetry $A_{CP}$ for $\cal B$ decays, such as $A_{CP}(Ξ_b^-\to K^0 Ξ^-)/A_{CP}(Ξ_b^-\to \bar K^0 Σ^-) = - Br(Ξ_b^- \to \bar K^0 Σ^-)/Br(Ξ_b^-…
We provide an overview of the latest progress in the study of CP violation and mixing in the $B$ meson decays. Studying the $B^0_d \to J/ψK^0_S$ and $B^0_s \to J/ψϕ$ decays, we focus on the determination of the mixing phases $ϕ_d$ and $ϕ_s$, including hadronic uncertainties with the help of the data. CP violation in the non-leptonic decays $B \to πK$ and $B^0_s \to D_s^{\mp} K^{\pm}$ indicate puzzling patterns. Could these puzzles indicate New Physics?
Using a coupled channel unitary approach, combining the heavy quark spin symmetry and the dynamics of the local hidden gauge, we investigate the meson-baryon interaction with hidden beauty and obtain several new states of $N^*$ around 11 GeV. We consider the basis of states $η_b N$, $ΥN$, $B Λ_b$, $B Σ_b$, $B^* Λ_b$, $B^* Σ_b$, $B^* Σ_b^*$ and find four basic bound states which correspond to $B Σ_b$, $B Σ_b^*$, $B^* Σ_b$ and $B^* Σ_b^*$, decaying mostly into $η_b N$ and $ΥN$ and with a binding energy about 50-130 MeV with respect to the thresholds of the corresponding channel. All of them have…
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
Imbalanced beauty-charmed baryons $ Ξ_{bc}^{+,0} $ are of great significance to the development of heavy flavor physics. In this work, we study the inclusive weak-annihilation decays of $Ξ_{bc}^{+,0}$ and their contributions to the $Ξ_{bc}^{+,0}$ lifetimes. For the calculation of the inclusive $Ξ_{bc}^{+,0}\to X_{cs}$ decay width where $X_{cs}$ stands for the sum of the final states with charm number +1 and strange number -1, we work in the heavy diquark effective theory which provides us with a convenient technical tool to construct the operator product expansion. The $Ξ_{bc}^{+,0}$ is consid…
We study the dependence on the quark mass of the compositeness of the lowest-lying odd parity hyperon states. Thus, we pay attention to $Λ-$like states in the strange, charm and beauty, sectors which are dynamically generated using a unitarized meson-baryon model. In the strange sector we use an SU(6) extension of the Weinberg-Tomozawa meson-baryon interaction, and we further implement the heavy-quark spin symmetry to construct the meson-baryon interaction when charmed or beauty hadrons are involved. In the three examined flavor sectors, we obtain two $J^P=1/2^-$ and one $J^P=3/2^-$ $Λ$ states…
The Heavy Flavor Averaging Group provides this Letter of Interest (LOI) as input to the Snowmass 2021 Particle Physics Community Planning Exercise organized by the Division of Particles and Fields of the American Physical Society. Research in heavy flavor physics is an essential component of particle physics, both within and beyond the Standard Model. To fully realize the potential of this field, we advocate strong support within the U.S. high energy physics program for ongoing and future experimental and theory research in heavy flavor physics.
We investigate the decay properties of some beauty and charm mesons with a phenomenological potential model. First, we consider the nonrelativistic Hamiltonian of the mesonic system with Coulomb plus exponential terms and study the wave function and the energy of the system using the variational approach. Thereby, we compute the masses, the decay constants, the leptonic branching fractions of heavy-light mesons and the mixing mass parameter $Δ{m_{B_q}}$. We study the radiative leptonic decay widths of ${D_s} \to γ\ell \bar ν$, ${D^ - } \to γ\ell \bar ν$ and the semileptonic decay widths of ${\…
Enhancement of preasymptotic effects in inclusive beauty decays
We extend Voloshin's recent analysis of charmed and beauty hyperon decays based on SU(3) symmetry and heavy quark effective theory, by introducing a rather moderate model-dependence, in order to obtain more predictive power, e.g. the values of lifetimes of the (Λ_{b},Ξ_{b}) hyperon triplet and the lifetime of Ω_{b}. In this way we obtain an improvement of the ratio τ(Λ_{b})/τ( B_{d} ^{0}) \sim 0.9 and the hierarchy of lifetimes τ(Λ_{b}) \simeq τ(Ξ_{b}^{0}) < τ(Ξ_{b}^{-}) < τ(Ω_{b}) with lifetimes of Ξ_{b}^{-} and Ω_{b} exceeding the lifetime of Λ_{b} by 22% and 35%, respectively.
We present the next-to-next-to-leading order (NNLO) QCD corrections to the decay constants for both the pseudoscalar and vector beauty-charmed mesons $B_{c}$ and $B^*_{c}$ in nonrelativistic QCD effective theory. Explicit NNLO calculation verified that the $B_c$ decay constant from pseudoscalar current is identical with the $B_c$ decay constant from axial-vector current. The NNLO result for the vector decay constant of $B^*_{c}$ meson is novel. Combined with the latest extraction of nonrelativistic QCD long-distance matrix elements of $B_c$ meson, we give the branching ratios of leptonic decay…
Our recently completed analysis of the decay constants of both pseudoscalar and vector beauty mesons reveals that in the bottom-quark sector two specific features of the sum-rule predictions show up: (i) For the input value of the bottom-quark mass in the $\overline{\rm MS}$ scheme $\overline{m}_b(\overline{m}_b)\approx4.18\;\mbox{GeV},$ the sum-rule result $f_B\approx210$-$220\;\mbox{MeV}$ for the $B$ meson decay constant is substantially larger than the recent lattice-QCD finding $f_B\approx190\;\mbox{MeV}.$ Requiring QCD sum rules to reproduce the lattice-QCD value of $f_B$ yields a signifi…
In this paper we examine the interaction of \bar B N, \bar B Δ, \bar B^* N and \bar B^* Δstates, together with their coupled channels, using a mapping from the light meson sector. The assumption that the heavy quarks act as spectators at the quark level automatically leads us to the results of the heavy quark spin symmetry for pion exchange and reproduces the results of the Weinberg Tomozawa term, coming from light vector exchanges in the extended local hidden gauge approach. With this dynamics we look for states dynamically generated from the interaction and find two states with nearly zero w…
Motivated by the latest discovery of a new tetraquark $T_{cc}^+$ with two charm quarks and two light antiquarks by LHCb Collaboration, we investigated the $DD^*$ hadronic molecule interpretation of $T_{cc}^+$. By calculation, the mass and the decay width of this new structure $T_{cc}^+$ can be understood in one-meson exchange potential model. The binding energies for these $DD^*$ hadronic molecules with $J^P=1^+$ are around $1MeV$. Besides, we also studied the possible beauty-partners $T_{bb}(10598)$ of hadronic molecule $T^+_{cc}$, which may be feasible in future LHCb experiments.
