CP violation in decay rates of charged bottom mesons

In the standard theory we discuss a mechanism of interference between two different tree-level charged current amplitudes to induce CP violation. The asymmetry between conjugate Cabibbo disfavoured modes of charged bottom meson decays is considered. Estimates for two-body decays ofB _u andB _c are presented. We find thatB _u ^? →D ^?+D ₀ ^* , for instance, can give a big CP asymmetry with values ≈1–50%, depending on the angle and phase parameters.     

<Emphasis Type="Italic">B</Emphasis>-meson decays into charmonium states in the ATLAS experiment

The paper presents several recent ATLAS results on the analyses of B-meson decays into charmonium states. These include the measurements of B⁺ mass and the fractions of J/ψ mesons produced in b-hadron decays in pp collisions at \(\sqrt s\) = 13 TeV in the center of mass system. The measured partial widths and polarizations in B _c ⁺ → J/ψD _s ^(*)+ decays and CP-violation parameters in B _s ⁰ → J/ψ? decays in pp collisions at 7 and 8 TeV in the center of mass system are also presented.     

B c-meson decays and lifetime within QCD sum rules

On the basis of three-point sum rules, the form factors for the semileptonic decays B _c ⁺ → B _s(B _s ^* )l ⁺ ν _l are calculated with allowance for α _s/v Coulomb corrections for the heavy quarkonium. Generalized relations associated with spin symmetry within the approach combining heavy-quark effective theory and nonrelativistic QCD are derived for form factors in the region of recoil momenta close to zero. The nonleptonic decays of the B _c meson are studied on the basis of the factorization hypothesis. By summing the main exclusive modes of c-quark decays and by using the results of a previous analysis of b-quark decays, the B _c-meson lifetime is estimated within QCD sumrules and within nonrelativistic QCD.     

Measurement of B d 0 - oscillations

B _d ⁰ meson oscillations are measured in hadronic Z⁰ decays using the charge of a lepton or the mean charge of an event hemisphere to sign the presence of a b or a b? quark when it is produced, and using the charge of a lepton emitted at large pt or of a D*^± to sign the presence of a B or a B? meson when it decays. With 3.2 million hadronic Z⁰ decays registered by DELPHI between 1991 and 1994, the mass difference Δm _d between the two physical B _d ⁰ states is measured in four channels: Taking into account the statistical overlap between these measurements and the common systematic uncertainties, the combined result is:      

Is there a 2++ glueball at 1410 MeV?

A glueball component of theJ ^PC =2⁺⁺ q \(\bar q\) isoscalar states is discussed within a simple mass mixing model. As the third isoscalar necessarily present in theq \(\bar q\) ?gg mixing scheme we assumeG(1410) recently claimed by ACCMOR Collaboration in the π^? p→K _s ⁰ K _s ⁰ n data. The hypothesis is found to be compatible with the available experimental data, including two-photon decay widths and radiativeJ/ψ decays.     

Neutrino production of charmed particles in a hybrid experiment E-564

Cryogenically sensitive nuclear emulsion was placed inside the 15-foot bubble chamber of FNAL and exposed to a wide-band energy (up to 200 GeV) neutrino beam. 194 charged-current neutrino interactions and 13 decays of charmed particles were registered. Using the nuclear emulsion as a vertex detector with the good spectrometric properties of the 15-foot bubble chamber has allowed the decays of charmed particles to be effectively analysed. Attentions is focussed on the new physical results. Λ _c ⁺ baryon andD _s ⁺ meson decay channels, production of charmed ∑ _c baryons and Λ _c ⁺ via ∑ _c . For the first time an event interpreted as production of the excited (c \(\overline s\) )-state with mass ～2790 MeV/c² has been registered.     

Nonfactorizable contributions to hadronic decays of charm mesons in the Cabibbo-suppressed modes

We investigate nonfactorizable contributions to charm meson decays into D → ππ/K K?/K K?*/K? K*/D → K*K?* modes. Obtaining the contributions from spectatorquark diagrams for N _c = 3, we determine the nonfactorizable isospin amplitudes required to explain the data for these modes. For these decays, we observe that ππ, πρ, decay modes favor a nonfactorizable-isospin-amplitudes ratio A ₀ ^nf /A ₂ ^nf equal to (1.123±0.158) and for K K?, K K?*, K? K* and K*K?* modes, the ratio of nonfactorizable amplitudes A ₀ ^nf and A ₁ ^nf turns out to be unity.     

Studying(\bar cs) spectroscopy in\bar vN collisions

Charmed strange meson neutrinoproduction is investigated. TheD _s ^? (1970) antineutrino production rate is measured. Two higher \((\bar cs)\) states are seen in the decay channels γD _s ^* (2110) andD ^*K, respectively.     

Z 0 boson decays to B^{(*)}_{c} meson and its uncertainties

The planned new e ⁺ e ^? collider with high luminosity shall provide another useful platform to study the properties of the doubly heavy B _c meson in addition to the hadronic colliders as LHC and TEVATRON. In the ‘New Trace Amplitude Approach’, we calculate the production of the spin-singlet B _c and the spin-triplet $B^{*}_{c}$ mesons through the Z ⁰ boson decays, where uncertainties for the production are also discussed. Our results show $\varGamma_{(^{1}S_{0})}=81.4^{+102.1}_{-40.5}$  KeV and $\varGamma_{(^{3}S_{1})}=116.4^{+163.9}_{-62.8}$  KeV, where the errors are caused by varying m _b and m _c within their reasonable regions.     

Weak decays of heavy mesons in the instantaneous Bethe Salpeter approach

In the framework of the instantaneous Bethe Salpeter equation we investigate weak decays ofB andD mesons. Mesons are described asq $\bar q$ states interacting via a mixture of a scalar and a vector confining kernel and a one gluon exchange. The model parameters are fixed by a fit to the meson mass spectrum including also the light mesons. We calculate form factors and compare our results to the pole dominance hypothesis. From a fit to ARGUS and CLEO data onB→D ^*?v semileptonic decay we extract the Cabbibo Kobayashi Maskawa matrix element to beV _cb =(0.032 ± 0.003)(1.49ps/τ _b )^1/2 The Isgur Wise function is calculated utilizing the heavy quark mass limit. Finally, we give some results on nonleptonic decays.     

Branching ratios for the decays of Ψ(3770) and ϒ(10580) mesons to a pair of light hadrons

The branching ratios for the exclusive decays of the heavy quarkonia Ψ(3770) and ?(10580) to a pair of light mesons [π ⁺ π ^-, $K\bar K$ , ρ(ω)π, ρ(ω)η, ρ(ω)η’, $K^* \bar K$ +c.c, ρ ⁺ ρ ^-, and $K^* \bar K^* $ ] and the branching ratios for the decays Ψ(3770) → J/Ψ + P(P = π ⁰, η) and ?(10580) → ?(1S) + P(P = π ⁰,η,η′), which involve a heavy quarkonium in the final state, are calculated with allowance for new data on the width of the D*^±(2010) meson and the mass differences between the charged and neutral beauty mesons (B ^±, on one hand, and B ⁰ and $\bar B^0 $ , on the other hand). The calculations are based on the model where the Okubo-Zweig-Iizuka rule is dynamically violated owing to the intermediate state $D\bar D (B\bar B)$ in the case of the Ψ(3770) [?(10580)] meson. The inclusive annihilation of Ψ(3770) and ?(10580) mesons to light hadrons is discussed.     

Doubly Charmed Exotic Mesons

We discuss the mass spectrum of doubly charmed mesons as hadronic molecules composed by D and D^* meson. Considering the heavy quark symmetry and chiral symmetry, we introduce the one-boson ( ${\pi , \rho , \omega}$ ) exchange potential between D and D^* meson. For all possible quantum numbers I(J ^P ) with isospin I, total angular momentum J( ≤ 2) and parity P, we solve the fully coupled channel Schrödinger equation. We find that in many quantum numbers the bound and resonant states composed by D or D^* meson can exist near the DD, DD^* and D^*D^* thresholds.     

Inclusive resonance production in 7.3 GeV/c\bar pp interactions

We present results on inclusive baryon and meson resonance production in \(\bar pp\) interactions at 7.3 GeV/c. Total inclusive and semi-inclusive cross sections are given for Δ(1232),∑ ^*(1385), ?⁰,f andK ^*±(892) production. For the meson resonances separation into annihilation and non-annihilation components has been made, the annihilation component being dominant at this energy. We find that the energy dependence of inclusive cross sections for ?⁰ production inpp interactions and \(\bar pp\) non-annihilations shows a type of scaling behaviour previously reported for ?, ψ, ψ′ and ? production inpp interactions.Δ ⁺⁺, ?⁰ andK ^*± production are studied in terms of Feynmanx,y ^* andp _T ² . For the vector mesons we compare they ^* andx dependences with the predictions of simple quark models.     

Long distance effects inb→s exclusive decays

We estimate long distance corrections to radiativeB →K ^*γ and to non leptonicB→Kπ,B→K ^*π,B→Kσ,B→K ^*σ,B→KΦ andB→K ^*Φ decays generated by the ( \(\overline b\) c) ( \(\overline c\) s) part of the non leptonic weak Hamiltonian. While vanishing in the vacuum saturation approximation, these corrections are finite if one includes single particle charmed states between the currents in the Hamiltonian. We find small effects in radiative decays, but significant contributions to several non leptonic processes.     

Semileptonic form factors D \rightarrow \pi, K and B \rightarrow \pi, K from a fine lattice

We extract the form factors relevant for semileptonic decays of D and B mesons from a relativistic computation on a fine lattice in the quenched approximation. The lattice spacing is a = 0.04 fm (corresponding to a ^-1 = 4.97 GeV), which allows us to run very close to the physical B meson mass, and to reduce the systematic errors associated with the extrapolation in terms of a heavy-quark expansion. For decays of D and D_s mesons, our results for the physical form factors at $\ensuremath q^2 = 0$ are as follows: $\ensuremath f_+^{D\rightarrow\pi}(0) = 0.74(6)(4)$ , $\ensuremath f_+^{D \rightarrow K}(0) = 0.78(5)(4)$ and $\ensuremath f_+^{D_s \rightarrow K} (0) = 0.68(4)(3)$ . Similarly, for B and B_s we find $\ensuremath f_+^{B\rightarrow\pi}(0) = 0.27(7)(5)$ , $\ensuremath f_+^{B\rightarrow K} (0) = 0.32(6)(6)$ and $\ensuremath f_+^{B_s\rightarrow K}(0) = 0.23(5)(4)$ . We compare our results with other quenched and unquenched lattice calculations, as well as with light-cone sum rule predictions, finding good agreement.     

Magnetostriction and thermal expansion of HoAl3(BO3)4

The magnetostriction and thermal expansion of rare-earth aluminoborate HoAl₃(BO₃)₄ have been studied theoretically. The calculated field and temperature dependences of the multipole moments of the Ho³⁺ ion in HoAl₃(BO₃)₄ made it possible to describe the known experimental data and to predict possible anomalies of thermal expansion. It has been shown that, for the direction of the field B ‖ c, the nonmonotonic character of magnetostriction along the axis a is determined by the multipole moments, the main of which is β _J 〈O ₄ ⁰ 〉. For B ‖ a and B ‖ b, the maximum moments are β _J 〈O ₄ ² 〉and α _J 〈O ₂ ² 〉; their variation with the field and temperature explain well the form of magnetostriction. It has been established that the greater value of magnetostriction Δa/a for B ‖ b than for B ‖ a and the greater value of magnetostriction for the field in the basal plane than for B ‖ c are caused by greater variations in the field of actual multipole moments.     

Charm photo-and electroproduction at high energies

The differential and total cross sections for the photoproduction of vector D* mesons and for their production in deep-inelastic interactions at the HERA collider are estimated on the basis of a model motivated by perturbative calculations within QCD. The proposed model makes it possible to take into account higher twists in the meson transverse momentum at pT～m _c and to reproduce correctly the dominance of c-quark fragmentation for p _T m _c . The possibility of the hadronization of an octet c $\bar q$ state into a meson is considered, whereby good agreement with experimental data is obtained both for the case of D*-meson photoproduction and for the case of D*-meson formation in a deep-inelastic process.     

Mass spectrum ofP-wave mesons

Mass splittings of mesons withL≧1 are discussed on the basis of a general spin-dependent potential consisting of a vector (V(r)) and a scalar (S(r)) part. For arbitraryV(r) andS(r), the four masses, for the three³ L _J and the one¹ L _J=L levels, are given in terms of only three unknown expectation values 〈(1/r)(dV/dr)〉, 〈d ² V/dr ²〉 and 〈(1/r)(dS/dr)〉. These expectations values are extracted for theP-wave \(u\bar s\) (or \(d\bar s\) ) mesons which are discussed in detail. It is argued that the 0⁺⁺ mass should be around 1150 to 1230 MeV, rather than at 1350 MeV. On comparing the expectation values for the \(u\bar s\) , \(c\bar c\) , \(b\bar b\) and the \(I = 1u\bar u\) systems, we find that they all scale asa+bμ, wherea andb are constants and μ is the reduced mass. Remarkably enough, we also find that theP-wave meson masses for these systems satisfy mass formulae of the formA+B(m₁+m₂), with constantA andB. It is shown that similar linear mass formulae also work forS-wave mesons. These facts seem to reveal a rather general property of \(q\bar q\) states.     

A new many-body solution of the Friedel resonance problem

It is numerically shown that the groundstate of the Friedel problem (consisting of a conduction band and a dresonance), occupied with (n+ 1) electrons, can be written as Ψ = (A a ₀ ^* +Bd*) Π _v=1 ⁿ a _v ^* Φ₀, where a ₀ ^* represents a localized conduction electron state, d* is the Friedel resonance state and Π _v=1 ⁿ a _v ⁸ Φ₀ is a Slater determinant of n single electron states a _t ^* , (Φ₀ is the vacuum state). The a _i ^* together with a ₀ ^* are part of a full ortho-normalized basis of the conductions band.     

Study of the centrally producedK 1 0 K ± π∓ system at 85 GeV/c

We have analyzed theK ₁ ⁰ K ^± π^? system in the reactions π⁺/pp→π⁺/p(K ₁ ⁰ K ^± π^?)p. A spin-parity analysis of theK ₁ ⁰ K ^± π^? system in the “4C” channel confirms the existence of the 1⁺⁺ E meson which decays mainly throughK ^* \(\bar K\) . The data allow the presence of a 0^?+ wave at a level of 14% of theE/ι signal. The production ofD andE mesons in the channels where theK ₁ ⁰ K ^± π^? system is produced along with a π⁰ or π⁺π^? system is suppressed.