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.
In this concluding talk, the advances in the Flavour Problem studies are discussed, following the structure of the presentations in the Conference. The subjects touched are organized as follows: Baryons, K-physics, Charm and Beauty production, Charm and Beauty decays, B-Mixing and CP-Violation, Heavy Quarkonium.
Recent results on the hadroproduction of charm and beauty are discussed in the context of the current theoretical and experimental status. The areas covered include production of open charm and beauty particles and charm and beauty quarkonia. Experimental results from both fixed target and colliding beam experiments are presented and compared to theoretical predictions. Predictions based on QCD perturbation theory are generally successful in explaining the shapes of differential cross sections but underestimate the scale of the cross section by factors of 2-3. An exception is production of the…
An update is given of the determination of leptonic decay constants of charm and beauty mesons in the framework of relativistic Hilbert moments and Laplace transform QCD sum rules.
A selfconsistent treatment of nonperturbative effects in inclusive nonleptonic and semileptonic decays of beauty and charm hadrons is presented. It is illustrated by calculating semileptonic branching ratios, lifetime ratios, radiative decay rates and the lepton spectra in semileptonic decays.
Exotic charmonium and bottonomium resonances recently discovered are discussed and interpreted as diquark-antidiquark states containing a pair of charm quarks and a pair of light, up and down, quarks. Successes, shortcomings and predictions of the model are illustrated.
The measurements of inclusive charm and beauty cross sections in deep-inelastic scattering $ep$ collisions at HERA are compared with the predictions of perturbative quantum chromodynamics from the CTEQ and MRST fitting groups, employing a range of theoretical schemes. The differences in the theoretical predictions are discussed and the theoretical uncertainties investigated.
We discuss the relative role of fragmentation and recombination processes for heavy flavour hadron production in different kinematical regions in high energy hadron-hadron and photon-hadron collisions. We predict several qualitative features which should be observed if our picture of heavy flavour production is consistent.
Using the Woods Saxon plus Coulomb type of interaction between two hadron molecules, we have calculated the binding energies and masses of the tetraquark states such as $D\bar{D}$, $D\bar{D}^*$, $D^*\bar{D}^*$, $D^+\bar{D}^*$ in the charm sector and $B\bar{B}$, $B^*\bar{B}^*$, $B\bar{B}^*$ in the bottom sector.
A number of ways are reviewed in which the study of charmed particles can answer corresponding questions about particles containing $b$ quarks. Topics include the properties of resonances, the magnitude of decay constants, the size of spin-dependent effects, and the hierarchy of lifetime differences.
The masses of $S$ and $P$ states, pseudoscalar and vector decay constants, leptonic, semileptonic decay widths of charm (D) and beauty (B) open flavour mesons have been computed in the framework of Coulomb and power potential of the form $V(r)=-\frac{α_c}{r}+A r^ν$. The results are compared with other theoretical as well as experimental results.
We discuss the spectral analysis of quarkonium states in a hot medium of deconfined quarks and gluons, and we show that such an analysis provides a way to determine the thermal properties of the quark-gluon plasma.
The production of charmed and beauty hadrons in proton-proton and proton-antiproton collisions at high energies is analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. It is shown that using both the QGSM and NLO QCD one can describe the experimental data rather successfully in a wide region of transverse momenta. We also present some predictions for the future experiments on the beauty baryon production in $pp$ collisions at LHC energies and on the charmed meson production in ${\bar p}p$ reactions at GSI energies.
A summary is given of the 5th International Conference on Hyperons, Charm and Beauty Hadrons held in Vancouver, Canada, June 25th to 29th, 2002. This series of conferences began in 1995 in Strasbourg, France, in large part through the efforts of A. Fridman, to whose memory this talk is dedicated. Topics reviewed include kaon and hyperon physics, charm and beauty production and decays, heavy baryons, the physics of the Cabibbo-Kobayashi-Maskawa matrix and CP violation, and precision electroweak analyses. An attempt is made to combine a review of the high points of the conference with a more gen…
In this QCD analysis, we investigate the impact of recent measurements of heavy-flavor charm and beauty cross sections data sets on the simultaneous determination of Parton Distribution Functions (PDFs) and the strong coupling, $α_s(M^2_Z)$. We perform three different fits based on Variable-Flavour Number Scheme (VFNS) at the Leading Order (LO) and Next-to-Leading Order (NLO) and choose the full HERA run I and II combined data as a new measurement of inclusive Deep Inelastic Scattering (DIS) cross sections for our base data set. We show that including charm and beauty cross sections data reduc…
A review is presented of the weak radiative decays of baryons.It includes an anlysis of the possible contributions of electromagnetic penguins to these decays,a survey of the difficulties still encountered in the sector of hyperon decays and a short account on some new developments on this topic. The theoretical treatments on charm and beauty baryon decays are summarized,with a good outlook for their detection.
The $B_c ^+$ family of $(c\bar{b})$ mesons with beauty and charm is of special interest among heavy quarkonium systems. The $B_c ^+$ mesons are intermediate between $(c\bar{c})$ and $(b\bar{b})$ states both in mass and size, so many features of the $(c\bar{b})$ spectrum can be inferred from what we know of the charmonium and bottomonium systems. The unequal quark masses mean that the dynamics may be richer than a simple interpolation would imply, in part because the charmed quark moves faster in $B_c$ than in the $J/ψ$. Close examination of the $B_c ^+$ spectrum can test our understanding of t…
Applying knowledge of the interaction between heavy quarks derived from the study of $c\overline{c}$ and $b\overline{b}$ bound states, we calculate the spectrum of $c\overline{b}$ mesons. We compute transition rates for the electromagnetic and hadronic cascades that lead from excited states to the $^1\text{S}_0$ ground state, and briefly consider the prospects for experimental observation of the spectrum.
the KM expectations of large CP asymmetries in $B$ decays are reviewed. I describe some observable signatures for the intervention of New Physics and list benchmarks defining the `ultimate' measurements in beauty physics. I also stress the need for dedicated searches for CP asymmetries in $D$ decays; attaining a sensitivity level of $10^{-3}$ could well reveal New Physics and thus lead to a new paradigm.
I review the properties of mesons with one heavy quark. I start by examining the predicted masses and widths in the context of the quark model and heavy quark effective theory. Some recent experimental results are described and I conclude with comments on potentially interesting future experimental studies.
We present the summary of the Working Group on lifetimes, mixing and weak mixing phases in charm and beauty mesons at the CKM 2010 workshop. In the past year or so good progress was achieved on both experimental and theoretical sides. While this yields improvement in our understanding of neutral meson mixing, further work is necessary to achieve the highest possible precision in order to investigate current hints for deviations between experiment and standard model predictions. With the recent LHC startup we see bright prospects for the near term future for huge improvements.
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.
Our community has focused on two-body final states in $B$ & $D$ decays. The SM produces at least the leading source of CP violation in $B$ transitions, none has been established yet in charm decays. It is crucial to measure three- and four-body FS with accuracy and to compare with predictions based on refined theoretical tools. Correlations between different final states (FS) based on CPT invariance are often not obvious, how to apply them and where. We have to probe regional asymmetries and use refined parametrization of the CKM matrix. One uses (broken) U- & V-spin symmetries for spectroscop…
We consider a U(5)-Nambu-Jona-Lasinio model with flavor-dependent couplings constants obtained from quark-antiquark polarization to investigate the role of the heavy quarks for light constituent quarks and mesons. A quantum mixing, due to the different representations of the flavor group needed to defined quarks and mesons, lead to charm and beauty sea quark contributions to properties of the light quark sector. For a given fitting procedure for the parameters of the model, the charm and beauty quark effective masses are freely varied from very small values to very large values (infinite). The…
We compare the numerical predictions for heavy quark production in high energy hadron collisions of the conventional QCD parton model and the $k_T$-factorization approach (semihard theory). The total production cross sections, one-particle rapidity and $p_T$ distributions as well as two-particle correlations are considered. The difference in the predictions of the two approaches is not very large, while the shapes of the distributions are slightly different.
Puzzles awaiting better experiments and better theory include: (1) the contradiction between good and bad SU(3) baryon wave functions in fitting Cabibbo theory for hyperon decays, strangeness suppression in the sea and the violation of the Gottfried Sum rule - no model fits all; (2) Anomalously enhanced Cabibbo-suppressed $D^+ \to K^{*+}(s\bar d)$ decays; (3) anomalously enhanced and suppressed $B \to η' X$ decays; (4) the OZI rule in weak decays; (5) Vector dominance ($W \to π, ρ, a_1, D_s, D^*_s $) in weak decays (6) Puzzles in doubly-cabibbo-suppressed charm decays.(7) Problems in obtaining…
The heavy quark expansion implemented through an operator product expansion provides us with a treatment of inclusive decays of beauty and charm hadrons that is genuinely derived from QCD,though it requires one additional assumption, namely that of 'local' quark-hadron duality. Subtleties in the application of factorization to hadronic expectation values are pointed out. The observed pattern in the charm lifetime ratios is reproduced in a semi-quantitative manner. The ratio $τ(Λ_b)/τ(B_d)$ cannot be pushed significantly below 0.9 -- unless one invokes a new hitherto unknown paradigm for evalua…
The production of heavy quarks (charm and beauty) provides unique insights into the transport properties of the Quark-Gluon Plasma (QGP) in heavy-ion collisions. Experimentally, the nuclear modification factor ${{R}_{\rm AA}}$ and the azimuthal anisotropy coefficient ${v}_{\rm 2}$ of heavy-flavor mesons are powerful observables to study the medium-related effects, such as energy loss and collectivity, on the heavy quark propagation through the QGP evolution. The latest measurements of the prompt and non-prompt open heavy-flavor hadrons allow a systematic comparison of the transport behaviors p…
Our community has to apply {\em non}-perturbative QCD on different levels of flavor dynamics in strange, charm \& beauty hadrons and even for top quarks. We need {\em consistent} parameterization of the CKM matrix and describe weak decays of beauty hadrons with {\em many-body} final states. It is crucial to use the {\em Wilsonian} OPE as much as possible and discuss "duality" in the worlds of quarks and hadrons. The pole mass of heavy quarks is {\em not} well-defined on the {\em non}-perturbative level -- i.e., it is {\em not} Borel summable in total QCD. We need a novel team to combine the st…
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 ${\…
We obtain tree-level estimates of various differential branching ratios of heavy baryon decays with massive sterile neutrinos $ν_{x}$ in the final state. Heavy sterile neutrinos can be searched for in heavy baryon decays with missing mass as a signature as well as in fixed target experiments, where heavy baryon decays contribute to sterile neutrino production, with sterile neutrino decays as a signature. Generally, charmed baryons are found to be less promising than charmed mesons, in contrast to b-hadrons. In the latter case, branching ratios of beauty mesons and baryons into sterile neutrino…
This note will be part of Chapter 6.5 of the ALICE Physics Performance Report (PPR), "ALICE Physics: Charm and Beauty", where the capabilities of ALICE for the detection of open heavy flavour particles will be described. We define here the present ALICE baseline for what concerns the heavy flavour production cross sections at LHC and the kinematical distributions of the heavy quark pairs. We start by qualitatively assessing the Bjorken x regimes accessible with charm and beauty measurements at LHC with ALICE (Section 1). In Section 2 we report the most recent results (and the uncertainties) of…
With the acceleration of lead nuclei in the LHC, heavy-ion physics will enter a new energy domain. One of the main novelties introduced by the 30-fold energy-jump from RHIC to the LHC is the abundant heavy-quark production. After discussing a few examples of physics issues that can be addressed using heavy quarks, we present a selection of results on the expected experimental capability of ALICE, the dedicated heavy-ion experiment at the LHC, in the open-heavy-flavour sector.
Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-quark masses. The impact of these results on measurements at the LHC and elsewhere is also addressed.
Inclusive heavy-flavour decays can be described through $1/m_Q$ expansions derived from QCD with the help of an operator product expansion. I sketch their methodology and apply them first to semileptonic B decays; $|V(cb)|$ can be extracted from $Γ_{SL}(B)$ and $\bar B \to l νD^*$ with the result: $|V(cb)|_{incl} = 0.0413 \pm 0.0016_{exp} \pm 0.002_{theor}$, $|V(cb)|_{excl} = 0.0377 \pm 0.0016_{exp} \pm 0.002_{theor}$. The lifetimes of charm and beauty hadrons are discussed. The charm lifetimes are predicted/reproduced as well as could be expected. Predictions on B meson lifetimes agree with a…
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.
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.
Charmed and beauty hadrons in matter are discussed within a unitarized coupled-channel model consistent with heavy-quark spin symmetry. We analyse the formation of D-mesic states as well as the propagation of charmed and beauty hadrons in heavy-ion collisions from LHC to FAIR energies.
We investigate the variation in the MMHT2014 PDFs when we allow the heavy quark masses $m_c$ and $m_b$ to vary away from their default values. We make PDF sets available in steps of $Δm_c =0.05~{\rm GeV}$ and $Δm_b =0.25~{\rm GeV}$, and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functions and note that in each case the heavy quark data, and the inclusive data, have a slight preference for lower masses than our default values. We provide PDF sets with 3 and 4 active quark flavours, as well as the standard va…
We predict several new bound states and resonances for B-pion, B-Kaon, and B-D S-wave elastic scattering, within the same model which was recently employed to explain the D*sJ(2317)+ meson. In the charm-nonstrange sector we find a (virtual ?) bound state close to the B-pion threshold, and moreover two nearby resonances of comparable width in the range 5.9 to 6.1 GeV. We obtain bound states B*s0(5570) in b-sbar and B*c0(6490) in bbar-c, as well as resonances at higher energies. No JP=0+ states are found at 5.6 GeV (in bbar-u/d), at 5.7 GeV (in b-sbar), or at 6.1 GeV (in bbar-c), where they are …
All the available experimental information on open charm and beauty mesons is used to classify the observed states in heavy quark doublets. The masses of some of the still unobserved states are predicted, in particular in the beauty sector. Adopting an effective Lagrangian approach based on the heavy quark and chiral symmetry, individual decay rates and ratios of branching fractions are computed, with results useful to assign the quantum numbers to recently observed charmed states which still need to be properly classified. Implications and predictions for the corresponding beauty mesons are p…
The recent successes of the SM do not weaken the arguments in favour of New Physics residing at the TeV scale. Finding and identifying it represents the prime challenge for a generation of high energy physicists. To differentiate between different scenarios of New Physics we need to analyze their impact on flavour dynamics. A continuing comprehensive program of heavy flavour studies instrumentalizing the high sensitivity of \cp analyses is intrinsically connected to LHC's core mission. In B decays we can typically expect no more than moderate deviations from SM predictions. $B_s$ transitions p…
More and more hadron states are found to be difficult to be accommodated by the quenched quark models which describe baryons as 3-quark states and mesons as antiquark-quark states. Dragging out an antiquark-quark pair from the gluon field in hadrons should be an important excitation mechanism for hadron spectroscopy. Our recent progress on the penta-quark states with hidden charm and beauty is reviewed.
Weak radiative decays of beauty baryons into strange baryons, induced by the electroweak penguin, are estimated by using a quark model approach. Relations between formfactors in the semileptonic and in the weak radiative decays are derived within the heavy quark effective theory. The partial decay widths are found to be of the order of $10^{-15}{\rm MeV}$ for $Λ_b\rightarrowΛγ$ and $Ξ_b\rightarrowΞγ$ and of the oder of $10^{-13}{\rm MeV}$ for $Ω_b\rightarrowΩγ$. The $Ω_b$ radiative decay is thus expected at the sizable branching ratio of approximately $10^{-4}$.
The parton model, a zero-order approximation in many treatments, is shown to be a ``semiclassical" model whose results for certain averages also hold (correspondence principle) in quantum mechanics. Algebraic techniques developed for the Mössbauer effect exploit simple features of commutators to obtain sum rules showing the validity of the parton model for $b \rightarrow c$ semileptonic decays in the classical limit, $\hbar \rightarrow 0$, where all commutators vanish, and in general, even when binding effects are included, for the lowest moments of the lepton energy spectrum at fixed 3-moment…
Quarks of different flavors have different masses, which will cause breaking of flavor symmetries of QCD. Flavor symmetries and their breaking in hadron spectroscopy play important role for understanding the internal structures of hadrons. Hadron spectroscopy with strangeness reveals the importance of unquenched quark dynamics. Systematic study of hadron spectroscopy with strange, charm and beauty quarks would be very revealing and essential for understanding the internal structure of hadrons and its underlying quark dynamics.
The effective theory for heavy quarks has additional symmetries with respect to QCD, which relate charm and beauty hadron masses. Assuming the spectrum of charmed particles, we predicted in a previous work the masses of some beauty particles. The predictions of the Lambda_b mass, M(Lambda_b)=5630 MeV, and of the B_s mass, M(B_s)=5379 MeV, are in agreement with present experimental data. We continue this work using recent experimental data on charm hadron masses. The results are: M(Sigma_b)=5822+-6 MeV, M(Sigma_b*)-M(Sigma_b)=33+-3 MeV, M(Omega_b)=6080+-7 MeV, M(Omega_b*)-M(Omega_b)=32+-3 MeV, …
We present a selfconsistent method for treating nonperturbative effects in inclusive nonleptonic and semileptonic decays of heavy flavour hadrons. These effects give rise to powerlike corrections $\propto 1/m_Q^n\,$, $n \ge 2$ with $m_Q$ denoting the heavy quark mass.The leading correction to the semileptonic branching ratio occurs for n=2. It is expressed in terms of the vector-pseudoscalar mass splitting: $δBR\ind{sl}/BR\ind{sl} \simeq BR\ind{nl}\, \cdot \,6\,(\,(M_V^2-M_P^2)/m_Q^2)\cdot (c_+^2 - c_-^2)/2N_c$ and yields a {\it reduction} of $BR\ind{sl}$. This nonperturbative correction contr…
At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and $\bar bc$ mesons in high energy $e^+e^-$ and hadronic collisions is dominated by parton fragmentation. We calculate the heavy quark fragmentation functions into the D-wave quarkonium and $\bar bc$ mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the $\bar b c$ meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a $\bar b$ antiquark to split into t…
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…
At hadron colliders the dominant production mechanism of $(\bar bc)$ mesons with large transverse momentum is due to parton fragmentation. We compute the rates and transverse momentum spectra for production of S-wave and P-wave $(\bar b c)$ mesons at the Tevatron via the direct fragmentation of the bottom antiquark as well as the Altarelli-Parisi induced gluon fragmentation. Since all the radially and orbitally excited $(\bar b c)$ mesons below the $BD$ flavor threshold will cascade into the pseudoscalar ground state $B_c$ through electromagnetic and/or hadronic transitions, they all contribut…
It has been realized for a long time that knowing the ηand η' wave functions in terms of quark and gluon components probes our understanding of non-perturbative QCD dynamics. Great effort has been given to this challenge -- yet no clear picture has emerged even with the most recent KLOE data. We point out which measurements would be most helpful in arriving at a more definite conclusion. A better knowledge of these wave functions will significantly help to disentangle the weight of different decay subprocesses in semi-leptonic decays of D^+, D_s^+ and B^+ mesons. The resulting insights will be…
The possibility of beauty baryon polarization measurement by cascade decay angular distribution analysis in the channel Lambda0 J/psi --> p pi- l+ l- is demonstrated. The error analysis shows that in the proposed LHC experiment ATLAS at the luminosity $10^{4} pb^{-1}$ the polarization can be measured with the statistical precision better than $δ=0.010$ for Lambda_b0 and $δ=0.17$ for Xi_b0.
Exclusive decays of B and D mesons are discussed with the focus on the theoretical problem how to calculate the relevant hadronic matrix elements of weak operators in the framework of QCD sum rules. The three lectures are devoted to 1. leptonic decays and decay constants 2. semileptonic decays and form factors 3. nonleptonic decays and nonfactorizable amplitudes. I shall introduce some of the basic concepts, describe various calculational techniques, and illustrate the numerical results. The latter are compared with lattice and quark model predictions and, where possible, with experimental dat…
We calculate the leading order QCD fragmentation functions for the production of $P$-wave charmed beauty mesons. Long-distance effects are factored into two nonperturbative parameters: the derivative of the radial wavefunction at the origin and a second parameter related to the probability for a $(\bar b c)$ heavy quark pair that is produced in a color-octet $S$-wave state to form a color-singlet $P$-wave bound state. The four $2P$ states and those $3P$ states which lie below the $BD$ flavor threshold eventually all decay into the $1S$ ground state $B_c$ through hadronic cascades or by emittin…