The $\bar B \bar B$ strong interaction with chiral perturbation theory
We study the strong interaction potentials of up to order with the heavy meson chiral perturbation theory. Besides the leading contributions from the contact terms we also consider the one-loop corrections to the contact diagrams and the contributions from the 2ϕ-exchange diagrams. Hopefully, the analytical structures of our result will be helpful in the extrapolation of the relevant heavy meson interaction in the lattice QCD simulation.

title: Pseudoscalar Meson and Decuplet Baryon Scattering Lengths
abstract: The excited states of the nucleon and their strong interactions with various hadrons play an important role in our understanding of non-perturbative QCD. Generally speaking, their coupling with the pseudoscalar pion, kaon and eta is governed by chiral dynamics. The first excited state of the nucleon, J = 3/2 ∆(1232), belongs to the lightest decuplet. It is degenerate with the nucleon in the large Nc limit [1, 2]. From the strong decay widths, one can extract the coupling constants of the pseudoscalar meson decuplet baryon interaction. Although it may be quite difficult to measure their scattering lengths experimentally, unlike in the pion-nucleon and kaon-nucleon cases [3–5], it is still interesting to study the scattering processes theoretically. As two well-known non-perturbative approaches of QCD at low energy, chiral perturbation theory and lattice QCD have been widely used in studying meson-baryon interactions [6–14]. With the explicitly consistent power counting scheme, the heavy baryon chiral perturbation theory (HBχPT) is a practical and useful tool in the study of the meson baryon scattering. The expansion is organized with p/Λχ, where p represents the momentum (mass) of the meson or the small residue momentum of the baryon in the non-relativistic limit, and Λχ = 4πfπ is the scale of chiral symmetry breaking. Numerically it is around the baryon mass in the chiral limit. Because of the large mass of the strange quark, the chiral corrections from the kaon and eta meson loops are significantly larger than that from the pion loop, which leads to the worse convergence of the chiral expansion in the SU(3) case. In HBχPT, the effects of excited baryons are encoded in the unknown low energy constants (LECs) in the Lagrangians. In the large Nc limit, one expects that the inclusion of the decuplet baryon contribution may partially cancel the octet contribution and be helpful to the chiral expansion. In order to investigate the contributions of the ∆, HBχPT with explicit spin-3/2 baryons and the small-scale expansion scheme have been developed in Refs. . Now the expansion is organized with ǫ, where ǫ means p in HBχPT or the mass difference δ between ∆ and the nucleon in the chiral limit, which is widely used in the exploration of the decuplet related processes [17–21]. There exists another power counting scheme “δ expansion” in the two-flavor case, where mπ scales as δ 2 [22–25]. In our previous work [21], we studied the decuplet contributions to the pseudoscalar meson octet baryon scattering lengths, which is an important observable reflecting their strong interaction near the threshold. The inclusion of the decuplet baryons does not improve the convergence significantly. In this paper, we will study the scattering lengths of the pseudoscalar mesons and the light decuplet baryons in the framework of the SU(3) heavy baryon chiral perturbation theory with explicit decuplet baryons. We will explore whether the small scale expansion works well in this case.

title: Pseudoscalar Goldstone bosons scattering off charmed baryons with chiral perturbation theory
abstract: We have systematically calculated the pseudoscalar Goldstone boson and charmed baryon scattering lengths to the third order with heavy baryon chiral perturbation theory. The scattering lengths can reveal the interaction of K Λ c , K Σ c , π Ω c , etc. For each channel, we take into account of the interaction between the external particle and every possible charmed baryon in the triplet, sextet, and excited sextet. We use dimensional regularization and modified minimal subtraction to get rid of the divergences in the loop-diagram corrections. We notice that the convergence of chiral expansion for most of the channels becomes better after we let the low energy constants absorb the analytic contributions of the loop-diagram corrections and keep the non-analytic terms only.

title: Chiral perturbation theory and the $\bar B \bar B$ strong interaction
abstract: We have calculated the potentials of the heavy (charmed or bottomed) pseudoscalar mesons up to $O(\epsilon^2)$ with the heavy meson chiral perturbation theory. We take into account the contributions from the football, triangle, box, and crossed diagrams with the 2$\phi$ exchange and one-loop corrections to the contact terms. We notice that the total 2$\phi$-exchange potential alone is attractive in the small momentum region in the channel ${\bar B \bar B}^{I=1}$, ${\bar B_s \bar B_s}^{I=0}$, or ${\bar B \bar B_s}^{I=1/2}$, while repulsive in the channel ${\bar B \bar B}^{I=0}$. Hopefully the analytical chiral structures of the potentials may be useful in the extrapolation of the heavy meson interaction from lattice QCD simulation.

title: Pseudoscalar Meson and Charmed Baryon Scattering Lengths
abstract: We have calculated the scattering lengths between the pseudoscalar meson and charmed triplet, sextet, and excited sextet baryon to the third order with the heavy baryon chiral perturbation theory. The chiral expansion of the pion channels converges well.

title: Pseudoscalar Mesons Scattering off D*-mesons with Chiral Perturbation Theory
abstract: We have systematically calculated the s-wave pseudoscalar mesons and D*- mesons scattering lengths to the third order with chiral perturbation theory, which will be helpful to reveal their strong interaction. We present the scattering lengths (1) in the framework of the heavy meson chiral perturbation theory and (2) in the framework of the infrared regularization.

title: Baryon masses with dynamical twisted mass fermions
abstract: We present results on the mass of the nucleon and the $\Delta$ using two dynamical degenerate twisted mass quarks. The evaluation is performed at four quark masses corresponding to a pion mass in the range of 690-300 MeV on lattices of size 2.1 fm and 2.7 fm. We check for cutoff effects by evaluating these baryon masses on lattices of spatial size 2.1 fm with lattice spacings $a(\beta=3.9)=0.0855(6)$ fm and $a(\beta=4.05)=0.0666(6)$ fm, determined from the pion sector and find them to be within our statistical errors. Lattice results are extrapolated to the physical limit using continuum chiral perturbation theory. 
The nucleon mass at the physical point provides a determination of the lattice spacing. Using heavy baryon chiral perturbation theory at ${\cal O}(p^3)$ we find $a(\beta=3.9)=0.0879(12)$ fm, with a systematic error due to the chiral extrapolation estimated to be about the same as the statistical error. This value of the lattice spacing is in good agreement with the value determined from the pion sector. We check for isospin breaking in the $\Delta$-system. We find that $\Delta^{++,-}$ and $\Delta^{+,0}$ are almost degenerate pointing to small flavor violating effects.

title: Form factors for rare B decays: strategy, methodology, and numerical study
abstract: llare presentlyaround 10 percent . So far, measurements are consistent with Standard Model expectations[2, 3]. Future experiments like LHCb are going to reduce the experimental uncertainties further.Thus, we are entering an era of precision ﬂavour physics, req uiring experimentalists and theoriststo focus on reducing statistical errors and employing multiple cross-checks to further quantifysystematic uncertainties.Lattice QCD can contribute to this by providing ﬁrst-principles nonperturbative calculationsof hadronic matrix elements relevant for rare B decays. In this report, we present our currentprogress in doing these computations. We use a non-relativistic effective action for the b quarkcalled moving NRQCD (mNRQCD) , which helps reduce discretisation errors in the ﬁnal statemeson at large recoil. This is achieved by giving the B meson a signiﬁcant velocity in the latticeframe, so that at a given q

title: Hadron properties from lattice QCD simulations with exact chiral symmetry

title: Measurement of the cross section for open-beauty production in photon–photon collisions at LEP
abstract: The cross section for open-beauty production in photon–photon collisions is measured using the whole high-energy and high-luminosity data sample collected by the L3 detector at LEP. This corresponds to 627 pb −1 of integrated luminosity for electron–positron centre-of-mass energies from 189 to 209 GeV. Events containing b quarks are identified through their semi-leptonic decay into electrons or muons.  These results are found to be in significant excess with respect to Monte Carlo predictions and next-to-leading order QCD calculations.

title: First observation of J / psi and psi(2S) decaying to n K0(S) anti-Lambda + c.c