Production of the Doubly Charmed Baryons at the SELEX experiment -- The double intrinsic charm approach

The high production rate and $\langle x_{F} \rangle > 0.33$ of the doubly charmed baryons measured by the SELEX experiment is not amenable to perturbative QCD analysis. In this paper we calculate the production of the doubly heavy baryons with the double intrinsic charm Fock states whose existence is rigorously predicted by QCD. The production rate and the longitudinal momentum distribution are both reproduced. We also show that the production rates of the doubly charmed baryons and double $J/\psi$ production observed by NA3 collaboration are comparable. Recent experimental results are reviewed. The production cross section of the doubly charmed baryons at a fixed-target experiment at the LHC is presented.Comment: The text is as published in Physics Letters

Future of B Physics at CDF and DO

In this contribution to the panel discussion on ``The Future of Hadron B Experiments'' held at the 8th International Conference on B Physics at Hadron Machines (Beauty 2002) at Santiago de Compostela, Spain, we explore the physics potential for B physics at CDF and DO in five years and beyond. After a brief introduction to precision flavour physics, we concentrate our discussion on the future of CP violation by evaluating the prospects for measuring the CKM angles beta, gamma and alpha at the Tevatron Collider experiments CDF and DO by the end of Run II.Comment: Posting for the archives: Contribution to Panel Discussion on "The Future of Hadron B Experiments". Pub. Proceedings Beauty 2002: 8th International Conference on B Physics at Hadron Machines, Santiago de Compostela, Spai

Predictions with Lattice QCD

In recent years, we used lattice QCD to calculate some quantities that were unknown or poorly known. They are the $q^2$ dependence of the form factor in semileptonic $D\to Kl\nu$ decay, the leptonic decay constants of the $D^+$ and $D_s$ mesons, and the mass of the $B_c$ meson. In this paper, we summarize these calculations, with emphasis on their (subsequent) confirmation by measurements in $e^+e^-$, $\gamma p$ and $\bar{p}p$ collisions.Comment: 5 pages; update of hep-lat/0509169, with experimental confirmation of form factors from Belle and fDs from BaBar; presented at SciDAC 2006 for the Fermilab Lattice, MILC, and HPQCD Collaboration

Theoretical Studies of the Structure of the Metal-carbon Composites on the Base of Acryle-nitrile Nanopolimer

The presence of the metal compounds in the acryle-nitrile nanopolimer (PPAN) leads to the formation of the metal nanoparticles. The metal-carbon nanocomposites based on PPAN including pair connections with iron and cobalt has been theoretically investigated. The spatial configuration of the nanocomposite for each option of the arrangement of metal atoms has been received. The analysis of the received results for all options of the arrangement of the metal atoms allowed defining the binding energy of the systems and the width of the forbidden gap ΔЕg of the nanocomposite. The analysis of the electronic and energy struc-tures of the system found out that the introduction of the metal atoms leaded to the essential reduction of the width of the forbidden zone of the composite in comparison with the pure PPAN. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3628

Probing Yukawa Unification with K and B Mixing

We consider corrections to the unification of down-quark and charged-lepton Yukawa couplings in supersymmetric GUTs, which links the large nu_tau-nu_mu mixing angle to b -> s transitions. These corrections generically occur in simple grand-unified models with small Higgs representations and affect s -> d and b -> d transitions via the mixing of the corresponding right-handed superpartners. On the basis of a specific SUSY-SO(10) model, we analyze the constraints from K-Kbar and B-Bbar mixing on the additional \tilde{d}_R-\tilde{s}_R rotation angle theta. We find that epsilon_K already sets a stringent bound on theta, theta^{max}=O(1 degree), indicating a very specific flavor structure of the correction operators. The impact of the large neutrino mixings on the unitarity triangle analysis is also briefly discussed, as well as their ability to account for the sizeable CP-violating phase observed recently in B_s -> psi phi decays.Comment: 19 pages. Discussion in Sec. 5.2 slightly extended; minor numerical modifications in Secs. 5.1 to 5.4, conclusions unchanged. Version to appear in JHE

A precise determination of the Bc mass from dynamical lattice QCD

We perform a precise calculation of the mass of the B_c meson using unquenched configurations from the MILC collaboration including 2+1 flavours of improved staggered quarks. Lattice NRQCD and the Fermilab formalism are used to describe the b and c quarks respectively. We find the mass of the B_c meson to be 6.304(16) GeVComment: Talk presented at Lattice2004(heavy), Fermilab, June 21-26. 3 pages, 2 figure

Chiral corrections and lattice QCD results for fBs/fBd and (Delta ms/Delta md)

It has been argued recently that the inclusion of the chiral logarithms in extrapolation of the lattice data can shift the value of the hadronic parameter xi = (fBs sqrt(B_{Bs}))/(fBd sqrt(B_{Bd})), from 1.16(6) to 1.32(10) and even higher. If true, that would considerably change the theoretical estimate for the ratio of oscillation frequencies in the neutral Bs- and Bd-systems, and would affect the standard CKM unitarity triangle analysis. In this letter we show that (fBs/fBd) \approx (fK/fpi), and thus the uncertainty due to the missing chiral logs is smaller than previously thought. By combining the NLO chiral expansion with the static heavy quark limit we obtain xi = 1.22(8).Comment: Published versio

Suppression of flavor symmetry breaking in B decay sum rules

While flavor symmetries are useful for studying hadronic B decays, symmetry relations for amplitudes and decay rates are usually violated by first order symmetry breaking corrections. We point out two cases in which first order symmetry breaking is suppressed by a small ratio of amplitudes: (1) An isospin sum rule for four $B\to K\pi$ decays, where isospin breaking is shown to be negligible. (2) An SU(3) sum rule for pairs of $B\to K\pi$ and $B\to K\eta_8$, generalized to pairs of $B\to K\pi, B\to K\eta$ and $B\to K\eta'$.Comment: 11 pages, small corrections, one reference added, submitted to Physics Letters

B_d and B_s mixing: mass and width differences and CP violation

B-B-bar mixing involves three physical parameters: the magnitudes of the off-diagonal elements of the mass and decay matrices and their relative phase. They are related to the mass and width differences between the mass eigenstates and to the CP asymmetry in flavour-specific decays, a_fs. Introducing a new operator basis I present new, more precise theory predictions for the width differences in the B_s and B_d systems: in the Standard Model one finds Delta Gamma_s = 0.088 +/- 0.017 ps^{-1} and Delta Gamma_d = (26.7 +5.8/-6.5) * 10^{-4} ps^{-1}. Updates of the mass differences Delta M_d and Delta M_s and of a_{fs}^d and a_{fs}^s are also presented. Then I discuss how various present and future measurements can be combined to constrain new physics. The extraction of a new CP phase phi_s^Delta from data on a_{fs}^s also profits from our new operator basis. Confronting our new formulae with D0 data we find that sin phi_s^Delta deviates from zero by 2 sigma.Comment: Eq. (7) and some typos corrected. 6 pages, 2 figures, talk at "Beauty 2006", 25-29 Sep 2006, Oxford, Englan