Radiation Genes: a database devoted to microarrays screenings revealing transcriptome alterations induced by ionizing radiation in mammalian cells

The analysis of the great extent of data generated by using DNA microarrays technologies has shown that the transcriptional response to radiation can be considerably different depending on the quality, the dose range and dose rate of radiation, as well as the timing selected for the analysis. At present, it is very difficult to integrate data obtained under several experimental conditions in different biological systems to reach overall conclusions or build regulatory models which may be tested and validated. In fact, most available data is buried in different websites, public or private, in general or local repositories or in files included in published papers; it is often in various formats, which makes a wide comparison even more difficult. The Radiation Genes Database (http://www.caspur.it/RadiationGenes) collects microarrays data from various local and public repositories or from published papers and supplementary materials. The database classifies it in terms of significant variables, such as radiation quality, dose, dose rate and sampling timing, as to provide user-friendly tools to facilitate data integration and comparison

Probing neutrino mass with multilepton production at the Tevatron in the simplest R-parity violation model

We analyze the production of multileptons in the simplest supergravity model with bilinear violation of R parity at the Fermilab Tevatron. Despite the small R-parity violating couplings needed to generate the neutrino masses indicated by current atmospheric neutrino data, the lightest supersymmetric particle is unstable and can decay inside the detector. This leads to a phenomenology quite distinct from that of the R-parity conserving scenario. We quantify by how much the supersymmetric multilepton signals differ from the R-parity conserving expectations, displaying our results in the $m_0 \otimes m_{1/2}$ plane. We show that the presence of bilinear R-parity violating interactions enhances the supersymmetric multilepton signals over most of the parameter space, specially at moderate and large $m_0$.Comment: 26 pages, 23 figures. Revised version with some results corrected and references added. Conclusions remain the sam

Electromagnetic Mass Splittings in Heavy Mesons

The electromagnetic contribution to the isomultiplet mass splittings of heavy mesons is reanalyzed within the framework of the heavy mass expansion. It is shown that the leading term in the expansion is given to a good approximation by the elastic term. $1/m_{Q}$-corrections can only be estimated, the main source of uncertainty now being inelastic contributions. The $1/m_{Q}$-corrections to the elastic term turn out to be relatively small in both D and B pseudoscalar mesons.Comment: 16 pages, report CEBAF-TH-92-26, one figure not included (available if requested

Understanding DsJ(2317)D_{sJ}(2317)

We analyze the hadronic and radiative decay modes of the recently observed $D_{sJ}(2317)$ meson, in the hypothesis that it can be identifield with the scalar $s_\ell^P={1\over 2}^+$ state of $c \bar s$ spectrum ($D_{s0}$). The method is based on heavy quark symmetries and Vector Meson Dominance ansatz. We find that the hadronic isospin violating mode $D_{s0} \to D_s \pi^0$ is enhanced with respect to the radiative mode $D_{s0} \to D_s^* \gamma$. The estimated width of the meson is $\Gamma(D_{s0})\simeq 7$ KeV.Comment: LaTex, 10 page

Radiative Heavy Meson Transitions

We evaluate the radiative and hadronic decay rates of the $D^*$ mesons using the Heavy Quark Effective Theory and the Vector Meson Dominance hypothesis. We also estimate the width of the $B^*$ electromagnetic transitions and the radiative decays of positive parity $J^P=0^+, 1^+$ charmed mesons.Comment: 12 pages, LaTex, BARI-TH/93-14

The Rate for e+e−→BB±π∓e^+e^-\to B B^\pm \pi^\mp and its Implications for the Study of CP Violation, BsB_s Identification, and the Study of BB Meson Chiral Perturbation Theory

H.~Yamamoto has proposed employing $B$ mesons produced in conjunction with a single charged pion at an $\Upsilon$ resonance for studies of CP violation in the neutral $B$ meson system at a symmetric $e^+$-$e^-$ collider. The sign of the charged pion would tag the neutral $B$ meson. We estimate this branching ratio, employing the heavy meson chiral effective field theory. We find a negligible branching ratio to $B B^{\pm} \pi^{\mp}$ at the $\Upsilon$(5S) and a branching ratio of only a few percent at the $\Upsilon$(6S). However, if nonresonant studies of neutral $B$ mesons should prove feasible, Yamamoto's proposal could be a good method for tagging neutral $B$'s for the study of CP violation at a symmetric collider. We also explore the possibility of studying $B_s$ at the $\Upsilon$(5S). The rate is low but depends sensitively on the precise value of the mass of the $B_s$. The background we compute is comparable to the rate at the largest allowed value of the $B_s$ mass. Finally, we discuss the extraction of the axial pion coupling to $B$ mesons from measurement of the B\bbar\pi branching fraction in a restricted region of phase space, where chiral perturbation theory should work well.Comment: 32 pages, 3 PS figures available upon request, MIT-CTP#215

Shear Alignment and Instability of Smectic Phases

We consider the shear flow of well-aligned one-component smectic phases, such as thermotropic smectics and lamellar diblock copolymers, below the critical region. We show that, as a result of thermal fluctuations of the layers, parallel ($c$) alignment is generically unstable and perpendicular ($a$) alignment is stable against long-wavelength undulations. We also find, surprisingly, that both $a$ and $c$ are stable for a narrow window of values for the anisotropic viscosity.Comment: To appear in PRL. Revtex, 1 figure

Inelastic J/ψJ/\psi production in polarized photon-hadron collisions

Presented here is a calculation of inelastic $J/\psi$ production in polarized photon-hadron collisions under the framework of NRQCD factorization formalism. We consider the photoproduction of \jpsi in the energy range relevant to HERA. The Weizs\"acker-Williams approximation is adopted in the evaluation of the cross sections for $ep$ collisions. We found that this process can give another independent test for the color-octet mechanism, and the different features for the two color-octet processes may provide further informations on the mechanism for inelastic \jpsi photoproduction. And the discrepancy on the production asymmetry $A$ between various sets of polarized gluon distribution functions is also found to be distinctive.Comment: 14pages, 6 PS figure

A Conjecture about Hadrons

We conjecture that in the chiral limit of QCD the spectrum of hadrons is comprised of decoupled, reducible chiral multiplets. A simple rule is developed which identifies the chiral representations filled out by the ground-state hadrons. Our arguments are based on the algebraic structure of superconvergence relations derived by Weinberg from the high-energy behavior of pion-hadron scattering amplitudes.Comment: 15 pages LaTe

D∗D^* Radiative Decays and Strong Coupling of Heavy Mesons with Soft Pions in a QCD Relativistic Potential Model

In the framework of a QCD inspired relativistic potential model, we evaluate radiative decay rates of heavy mesons and their coupling with soft pions. The agreement with the existing experimental data is satisfactory. In the limit $m_Q \to \infty$ one obtains results in agreement with the Heavy Quark Effective Theory and is able to predict the values of the relevant couplings; in particular, for the scaled $B^*B \pi$ strong coupling constant $g$, we find that the non relativistic constituent quark model prediction $g=1$ is modified, by the inclusion of the relativistic effects due to the light quarks, to the value $g=1/3$, in agreement with recent QCD sum rules determination.Comment: LaTex, 11 pages, BARI-TH/94-18