De Haas-van Alphen studies of electron-scattering in dilute copper-based alloys

We have used the de Haas-van Alphen (dHvA) effect to study the relaxation times of “neck” and “belly” electrons in copper containing a range of dilute heterovalent and transition-metal solutes. The scattering (Dingle) temperaturex is derived from the variation of signal amplitude with magnetic field at a fixed temperature. Values ofx are believed accurate to within 0.1°K in a range ofx _N(neck) from ≃0.4°K to ≃6°K andx _B(belly) from ≃0.2°K to ≃3°K. Our results may be summarized as follows:Heterovalent solutes (Zn, Cd, Al; up to 0.1 at. %) .Transition-metal solutes (Ni, Co, Fe, Mn, Cr; up to 0.05 at.-%) . An anomalous dependence of dHvA amplitude on magnetic field has been observed for belly oscillations in several very dilute Cu Cr alloys. This anomaly is both concentration and temperature-sensitive, and is probably related to the Kondo effect.     

Neutral meson oscillations and equivalence principle for particles and antiparticles

Oscillations of neutral meson (K ⁰-$ \overline {K^0 } $ \overline {K^0 } , D ⁰-$ \overline {D^0 } $ \overline {D^0 } , and B ⁰-$ \overline {B^0 } $ \overline {B^0 } are extremely sensitive to the meson and antimeson energies at rest. This energy is determined as mc ²—with the corresponding inertial mass—and as the energy of gravitational interaction. Assuming that the CPT theorem is correct for inertial masses and estimating the gravitational potential for which the largest contribution originates from the field of the galaxy center, we obtain the estimate from experimental data on K ⁰-$ \overline {K^0 } $ \overline {K^0 } oscillations:

Local-duality QCD sum rules for strong isospin breaking in the decay constants of heavy–light mesons

We discuss the leptonic decay constants of heavy–light mesons by means of Borel QCD sum rules in the local-duality (LD) limit of infinitely large Borel mass parameter. In this limit, for an appropriate choice of the invariant structures in the QCD correlation functions, all vacuum-condensate contributions vanish and all nonperturbative effects are contained in only one quantity, the effective threshold. We study properties of the LD effective thresholds in the limits of large heavy-quark mass \(m_Q\) and small light-quark mass \(m_q\). In the heavy-quark limit, we clarify the role played by the radiative corrections in the effective threshold for reproducing the pQCD expansion of the decay constants of pseudoscalar and vector mesons. We show that the dependence of the meson decay constants on \(m_q\) arises predominantly (at the level of 70–80%) from the calculable \(m_q\)-dependence of the perturbative spectral densities. Making use of the lattice QCD results for the decay constants of nonstrange and strange pseudoscalar and vector heavy mesons, we obtain solid predictions for the decay constants of heavy–light mesons as functions of \(m_q\) in the range from a few to 100 MeV and evaluate the corresponding strong isospin-breaking effects: \(f_{D^+} - f_{D^0}=(0.96 \pm 0.09) \ \mathrm{MeV}\), \(f_{D^{*+}} - f_{D^{*0}}= (1.18 \pm 0.35) \ \mathrm{MeV}\), \(f_{B^0} - f_{B^+}=(1.01 \pm 0.10) \ \mathrm{MeV}\), \(f_{B^{*0}} - f_{B^{*+}}=(0.89 \pm 0.30) \ \mathrm{MeV}\).     

Looking for new physics in leptonic and semileptonic decays of <Emphasis Type="Italic">B</Emphasis>-meson

We probe possible new physics (NP) effects beyond the standard model (SM) in the decays \({\overline B ^0} \to \pi \tau \overline \upsilon ,{\overline B ^0} \to \rho \tau \overline \upsilon ,and{\overline B ^0} \to \tau \overline \upsilon \), based on an effective Hamiltonian including non-SM operators. Experimental constraints on different NP scenarios are provided by recent measurements of the ratios \({{R\left( {{D^{\left( * \right)}}} \right) \equiv B\left( {{{\overline B }^0} \to {D^{\left( * \right)}}\tau \overline \upsilon } \right)} \mathord{\left/ {\vphantom {{R\left( {{D^{\left( * \right)}}} \right) \equiv B\left( {{{\overline B }^0} \to {D^{\left( * \right)}}\tau \overline \upsilon } \right)} {B\left( {{{\overline B }^0} \to {D^{\left( * \right)}}\mu \overline \upsilon } \right)}}} \right. \kern-\nulldelimiterspace} {B\left( {{{\overline B }^0} \to {D^{\left( * \right)}}\mu \overline \upsilon } \right)}}\), as well as the branching \(B\left( {{B^ - } \to \tau \overline \upsilon } \right)\). The corresponding hadronic form factors and leptonic decay constants are calculated in the covariant confined quark model developed by us.     

Neutralb→c non leptonic decays and their role in the search forB→K *γ

We estimate the rates ofB ⁰ decays into neutral charmed final states \(B^0 \to \overline {D^{ * 0} } \gamma ,B^0 \to \overline {D^{ * 0} } \pi ^0 ,B^0 \to \overline {D^0 } \pi ^0 ,B^0 \to \overline {D^0 } \omega \) , by considering factorizable, vector meson dominance and long distance contributions. We also discuss the role of these decay modes as a source of background events in the search for exclusiveb→sγ transitions in very high energy experiments, e.g. at LEP.     

Interference of Nonstandard Interactions with Standard Model in $${B^0} \to {\pi ^0}\bar vv$$, $$B_c^ - \to {D^ - }\bar vv$$Bc−→D−v¯v and $$\bar B_s^0 \to {K^0}\bar vv$$B¯s0→K0v¯v Decays

We study the contributions of nonstandard neutrino interactions (NSI) to the rare decays of pseudoscalar mesons involving neutrinos in the final state \({B^0} \to {\pi ^0}\bar vv\), \(B_c^ - \to {D^ - }\bar vv\) and \(\bar B_s^0 \to {\bar K^0}\bar vv\), It is pointed that dominant contribution comes from the interference between standard model and nonstandard interaction We predict limits on NSIs free parameter ε ^uL _ττ and compare them with experimental data. We further compare our results with perturbative QCD (pQCD) and QCD results for these reactions.     

NLO contributions to <Emphasis Type="Italic">B</Emphasis>→<Emphasis Type="Italic">KK</Emphasis><Superscript>*</Superscript> decays in the pQCD approach

We calculate the important next-to-leading-order (NLO) contributions to the B→KK ^* decays from the vertex corrections, the quark loops, and the magnetic penguins in the perturbative QCD (pQCD) factorization approach. The pQCD predictions for the CP-averaged branching ratios are , , and Br(B ⁰→K ⁺ K ^*−+K ⁻ K ^*+)≈1.3×10⁻⁷, which agree well with both the experimental upper limits and the predictions based on the QCD factorization approach. Furthermore, the CP violating asymmetries of the considered decay modes are also evaluated. The NLO pQCD predictions for and decays are and .     

Theg-factor of the 181 keV level of99Tc and hyperfine fields of Tc in Fe,Co, Ni

Theg-factor of the 181 keV-level of⁹⁹Tc has been redetermined by the spin rotation method. Measurements with polycrystalline sources of Tc in Fe, Co, and Ni yielded values of the hyperfine fields at the Tc nucleus. $$\begin{gathered} g = + 1.310(25) \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Fe) = ( - )290(15)kOe \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Co) = ( - )170(5)kOe \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Ni) = - 47.8(1.5)kOe. \hfill \\ \end{gathered} $$      

Mass mixing,CP violation and left-right symmetry for heavy neutral mesons

We investigate \(M^0 - \bar M^0 \) mixing and CP violation in the minimal left-right symmetric gauge model with spontaneous P and CP violation. The dominant contributions to the mixing amplitude including QCD corrections are calculated explicitly for \(B^0 - \bar B^0 \) . While the amount of mixing is not much changed with respect to the standard model leftright symmetry can give rise to significantly larger CP violation in the \(B_s^0 - \bar B_s^0 \) system (up to two orders of magnitude for the dilepton charge asymmetry). Sizable CP violating effects require that the left-right contribution to theK _L K _S mass difference has the same sign as the standard model contribution. We also comment on \(D^0 - \bar D^0 \) mixing including a careful discussion of the standard model prediction for the short distance part.     

Constraints on the squark mass matrix from CP-violation and SUSY predictions for theB^0 - \bar B^0 systems

The parametersc andA of the squark mass matrix, which control flavour violation and left-right maxing respectively, are constrained by fitting ∈ and ∈′. The predictions for mixing and CP-violation in the \(B^0 - \bar B^0 \) system are calculated and then compared with both the predictions of the standard model and the available experimental data.     

Hierarchy of Poisson brackets for elements of a scattering matrix

The infinite family of Poisson brackets between the elements of a scattering matrix is calculated for the linear matrix spectral problem.     

Das Quadrupolmoment des 2,3 MeV-Zustandes in120Sn

Time differentialγγ-angular correlation measurements have been performed to determine the electric interaction of the 2.3 MeVI=5^? state of¹²⁰Sn in different polycristalline antimony compounds. A calibration of the field gradient was achieved by Mößbauerexperiments with the 23.8 keVI=3/2⁺ state in¹¹⁹Sn using identical sources. From the ratio of the measured electric interactions the ratio of the quadrupole moments is deduced as: $$\left| {\frac{{Q(2.3{\mathbf{ }}MeV level,{\mathbf{ }}I = 5^ - ,^{120} Sn)}}{{Q(2.8{\mathbf{ }}keV level,{\mathbf{ }}I = {3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}^ + ,^{119} Sn)}}} \right| = 2.86(15)$$ . Using 0.06 (2) b for the quadrupole moment of the 23.8 keV level in¹¹⁹Sn one gets for the quadrupole moment of the 2.3 MeV level in¹²⁰Sn ¦Q(2.3 MeV level,I=5^?,¹²⁰Sn)¦=0.021 (8) b.     

Theoretical study of collision and collision-free radiative lifetimes of {{\text{S}}_2}\left( {{{\text{B}}^3}\Sigma_{\text{u}}^{-} \left( {{\upsilon^{\prime}} = 0 - 9} \right)} \right)

We calculate multireference configuration-interaction wavefunctions and the potential-energy curves for the $ {B^3}\Sigma_u^{-} $ and $ {X^3}\Sigma_g^{-} $ states of the collision-free S₂ molecule and the T-shape collision complex S₂?CHe using cc-pVQZ basis sets. We obtain the transition dipole moments of the $ {{\text{S}}_2}\left( {{B^3}\Sigma_u^{-} \to {X^3}\Sigma_g^{-} } \right) $ and the Franck?CCondon factors between the vibrational levels of this two states. We evaluate the radiative lifetimes of $ {{\text{S}}_2}\left( {{B^3}\Sigma_u^{-} \left( {{\upsilon^{\prime}} = 0 - 9} \right)} \right) $ levels of the collision complex and the collision-free molecule and compare them with the experiments. The collision provides little change in the radiative lifetimes of $ {{\text{S}}_2}\left( {{B^3}\Sigma_u^{-} \left( {{\upsilon^{\prime}} = 0 - 9} \right)} \right) $ according to the previous calculations. We obtain excellent agreement between the theoretical results and the experiments. The data calculated are very useful in the study of the microwave-driven high-pressure sulfur lamp and an S₂ laser pumped by a transverse fast discharge.     

Consequences of R-parity violating interactions for anomalies in $${\bar{B}}\rightarrow D^{(*)} \tau {\bar{\nu }}$$ and $$b\rightarrow s \mu ^+\mu ^-$$b→sμ+μ-

We investigate the possibility of explaining the enhancement in semileptonic decays of \({\bar{B}} \rightarrow D^{(*)} \tau {\bar{\nu }}\), the anomalies induced by \(b\rightarrow s\mu ^+\mu ^-\) in \({\bar{B}}\rightarrow (K, K^*, \phi )\mu ^+\mu ^-\) and violation of lepton universality in \(R_K = \mathrm{Br}({\bar{B}}\rightarrow K \mu ^+\mu ^-)/\mathrm{Br}({\bar{B}}\rightarrow K e^+e^-)\) within the framework of R-parity violating MSSM. The exchange of down type right-handed squark coupled to quarks and leptons yields interactions which are similar to leptoquark induced interactions that have been proposed to explain the \({\bar{B}} \rightarrow D^{(*)} \tau {\bar{\nu }}\) by tree level interactions and \(b\rightarrow s \mu ^+\mu ^-\) anomalies by loop induced interactions, simultaneously. However, the Yukawa couplings in such theories have severe constraints from other rare processes in B and D decays. Although this interaction can provide a viable solution to the \(R(D^{(*)})\) anomaly, we show that with the severe constraint from \({\bar{B}} \rightarrow K \nu {\bar{\nu }}\), it is impossible to solve the anomalies in the \(b\rightarrow s \mu ^+\mu ^-\) process simultaneously.     

A Heisenberg Double Addition to the Logarithmic Kazhdan–Lusztig Duality

For a Hopf algebra B, we endow the Heisenberg double \({\mathcal{H}(B^*)}\) with the structure of a module algebra over the Drinfeld double \({\mathcal{D}(B)}\). Based on this property, we propose that \({\mathcal{H}(B^*)}\) is to be the counterpart of the algebra of fields on the quantum-group side of the Kazhdan–Lusztig duality between logarithmic conformal field theories and quantum groups. As an example, we work out the case where B is the Taft Hopf algebra related to the \({\overline{\mathcal{U}}_{\mathfrak{q}} s\ell(2)}\) quantum group that is Kazhdan–Lusztig-dual to (p,1) logarithmic conformal models. The corresponding pair \({(\mathcal{D}(B),\mathcal{H}(B^*))}\) is “truncated” to \({(\overline{\mathcal{U}}_{\mathfrak{q}} s\ell2,\overline{\mathcal{H}}_{\mathfrak{q}} s\ell(2))}\), where \({\overline{\mathcal{H}}_{\mathfrak{q}} s\ell(2)}\) is a \({\overline{\mathcal{U}}_{\mathfrak{q}} s\ell(2)}\) module algebra that turns out to have the form \({\overline{\mathcal{H}}_{\mathfrak{q}} s\ell(2)=\mathbb{C}_{\mathfrak{q}}[z,\partial]\otimes\mathbb{C}[\lambda]/(\lambda^{2p}-1)}\), where \({\mathbb{C}_{\mathfrak{q}}[z,\partial]}\) is the \({\overline{\mathcal{U}}_{\mathfrak{q}} s\ell(2)}\)-module algebra with the relations z ^p  = 0, ? ^p  = 0, and \({\partial z = \mathfrak{q}-\mathfrak{q}^{-1} + \mathfrak{q}^{-2} z\partial}\).     

New physics effects in charm meson decays involving $$c \rightarrow u l^+ l^- (l_i^{\mp } l_j^{\,\pm \,})$$ transitions

We study the effect of the scalar leptoquark and \(Z^\prime \) boson on the rare decays of the D mesons involving flavour changing transitions \(c \rightarrow u l^+ l^- (l^{\mp }_i l^{\,\pm \,}_j)\). We constrain the new physics parameter space using the branching ratio of the rare decay mode \(D^0 \rightarrow \mu ^+ \mu ^-\) and the \(D^0 - {\bar{D}}^0\) oscillation data. We compute the branching ratios, forward–backward asymmetry parameters and flat terms in \(D^{+(0)} \rightarrow \pi ^{+(0)} \mu ^+ \mu ^-\) processes using the constrained parameters. The branching ratios of the lepton flavour violating D meson decays, such as \(D^0 \rightarrow \mu e, ~\tau e\) and \(D^{+(0)} \rightarrow \pi ^{+(0)} \mu ^- e^+\) are also investigated.     

Editorial

The production of charmed mesons ,D ^± , andD ^*± is studied in a sample of 478,000 hadronicZ decays. The production rates are measured to be

Study of B c → D π in the perturbative QCD approach

We investigate the branching ratios and direct CP-asymmetries of the and decays in the PQCD approach. All the diagrams with emission topology or annihilation topology are calculated strictly. A branching ratio of 10^-6 and 10^-7 for and decay is predicted, respectively. Because of the different weak phase and strong phase from penguin operator and two kinds of tree operator contributions, we predict a possible large direct CP-violation: and when γ = 55°, which can be tested in the coming LHC. PACS: 13.25.Hw, 12.38.Bx