Burkhardt-Cottingham sum rule and forward spin polarizabilities in Heavy Baryon Chiral Perturbation Theory

We study spin-dependent sum rules for forward virtual Compton scattering(VVCS) off the nucleon in heavy baryon chiral perturbation theory at order $O(p^4)$. We show how these sum rules can be evaluated from low energy expansions (in the virtual photon energy) of the forward VVCS amplitudes. We study in particular the Burkhardt -Cottingham sum rule in HBChPT and higher terms in the low energy expansion, which can be related to the generalized forward spin polarizabilities of the nucleon. The dependence of these observables on the photon virtuality $Q^2$ can be accessed, at small and intermediate $Q^2$ values, from existing and forthcoming data at Jefferson Lab.Comment: 16 pages,4 fig

Fundamental, Quantitative Traits of the “Sociotype”

In whatever domain of life, from cells to organisms to societies, communicative exchanges underlie the formation and maintenance, and decay, of the emerging collective structures. It can be clearly seen in the human social world. The different classes of social bonds in a complex society revolve around, and are intimately related with, the communicative relationships that every individual entertains—essentially via face-to-face conversation. In the present work we have investigated the fundamental metrics of both social bonds and communicative exchanges along the development of the “sociotype” construct. It is a new approach developed by the authors within the genotype-phenotype-sociotype conceptual triad. The sociotype means the relative constancy, or better the similar fabric, of the social world in which each individual life is developed. In order to ascertain the metrics of the fundamental quantitative traits inherent in the sociotype, a fieldwork involving a total of 1475 individuals (68.59% female, and 49.79 mean age, SD = 21.47) was carried out. The four relational realms of family, friends, work/study, and acquaintances were investigated. The overall results about conversation time (an average of 220 min/day), and about the number of social bonds (an average of 98), differ from previous assumptions, such as Dunbar's number or Killworth's number. Other results about gender, age, and use of social media and Internet contribute to highlight significant differences among the different social segments, and particularly the diminished “sociotype” of the elderly. Finally, it is curious that a non-Gaussian distribution has been obtained for the specific population allotment of these metrics, and intriguingly the Planckian distribution equation (PDE) appears to be a most cogent fit

Quark initiated coherent diffractive production of muon pair and W boson at hadron colliders

The large transverse momentum muon pair and W boson productions in the quark initiated coherent diffractive processes at hadron colliders are discussed under the framework of the two-gluon exchange parametrization of the Pomeron model. In this approach, the production cross sections are related to the small-x off-diagonal gluon distribution and the large-x quark distribution in the proton (antiproton). By approximating the off-diagonal gluon distribution by the usual gluon distribution function, we estimate the production rates of these processes at the Fermilab Tevatron.Comment: 11pages, 6 PS figures, to appear in PR

The Jlab Upgrade - Studies of the Nucleon with CLAS12

An overview is presented on the program to study the nucleon structure at the 12 GeV JLab upgrade using the CLAS12 detector. The focus is on deeply virtual exclusive processes to access the generalized parton distributions, semni-inclusive processes to study transverse momentum dependent distribution functions, and inclusive spin structure functions and resonance transition form factors at high Q^2 and with high precision.Comment: 7 pages, 12 figures, NSTAR 2007 conference, Bonn, September 5-8, 200

Poincare Invariant Algebra From Instant to Light-Front Quantization

We present the Poincare algebra interpolating between instant and light-front time quantizations. The angular momentum operators satisfying SU(2) algebra are constructed in an arbitrary interpolation angle and shown to be identical to the ordinary angular momentum and Leutwyler-Stern angular momentum in the instant and light-front quantization limits, respectively. The exchange of the dynamical role between the transverse angular mometum and the boost operators is manifest in our newly constructed algebra.Comment: 21 pages, 3 figures, 1 tabl

Diffractive light quark jet production at hadron colliders in the two-gluon exchange model

Massless quark and antiquark jet production at large transverse momentum in the coherent diffractive processes at hadron colliders is calculated in the two-gluon exchange parametrization of the Pomeron model. We use the helicity amplitude method to calculate the cross section formula. We find that for the light quark jet production the diffractive process is related to the differential off-diagonal gluon distribution function in the proton. We estimate the production rate for this process at the Fermilab Tevatron by approximating the off-diagonal gluon distribution function by the usual diagonal gluon distribution in the proton. And we find that the cross sections for the diffractive light quark jet production and the charm quark jet production are in the same order of magnitude. We also use the helicity amplitude method to calculate the diffractive charm jet production at hadron colliders, by which we reproduce the leading logarithmic approximation result of this process we previously calculated.Comment: 15 pages, 4 PS figures, Revte

Ty1 insertions in intergenic regions of the genome of Saccharomyces cerevisiae transcribed by RNA polymerase III have no detectable selective effect

The retrotransposon Ty1 of Saccharomyces cerevisiae inserts preferentially into intergenic regions in the vicinity of RNA polymerase III-transcribed genes. It has been suggested that this preference has evolved to minimize the deleterious effects of element transposition on the host genome, and thus to favor their evolutionary survival. This presupposes that such insertions have no selective effect. However, there has been no direct test of this hypothesis. Here we construct a series of strains containing single Ty1 insertions in the vicinity of tRNA genes, or in the rDNA cluster on chromosome XII, which are otherwise isogenic to strain 337, containing zero Ty1 elements. Competition experiments between 337 and the strains containing single Ty1 insertions revealed that in all cases, the Ty1 insertions have no selective effect in rich medium. These results are thus consistent with the hypothesis that the insertion site preference of Ty1 elements has evolved to minimize the deleterious effects of transposition on the host genome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72266/1/S1567-1356_03_00199-5.pd

DD-dimensions Dirac fermions BEC-BCS cross-over thermodynamics

An effective Proca Lagrangian action is used to address the vector condensation Lorentz violation effects on the equation of state of the strongly interacting fermions system. The interior quantum fluctuation effects are incorporated as an external field approximation indirectly through a fictive generalized Thomson Problem counterterm background. The general analytical formulas for the $d$-dimensions thermodynamics are given near the unitary limit region. In the non-relativistic limit for $d=3$, the universal dimensionless coefficient $\xi ={4}/{9}$ and energy gap $\Delta/\epsilon_f ={5}/{18}$ are reasonably consistent with the existed theoretical and experimental results. In the unitary limit for $d=2$ and T=0, the universal coefficient can even approach the extreme occasion $\xi=0$ corresponding to the infinite effective fermion mass $m^*=\infty$ which can be mapped to the strongly coupled two-dimensions electrons and is quite similar to the three-dimensions Bose-Einstein Condensation of ideal boson gas. Instead, for $d=1$, the universal coefficient $\xi$ is negative, implying the non-existence of phase transition from superfluidity to normal state. The solutions manifest the quantum Ising universal class characteristic of the strongly coupled unitary fermions gas.Comment: Improved versio

Angular Conditions,Relations between Breit and Light-Front Frames, and Subleading Power Corrections

We analyze the current matrix elements in the general collinear (Breit) frames and find the relation between the ordinary (or canonical) helicity amplitudes and the light-front helicity amplitudes. Using the conservation of angular momentum, we derive a general angular condition which should be satisfied by the light-front helicity amplitudes for any spin system. In addition, we obtain the light-front parity and time-reversal relations for the light-front helicity amplitudes. Applying these relations to the spin-1 form factor analysis, we note that the general angular condition relating the five helicity amplitudes is reduced to the usual angular condition relating the four helicity amplitudes due to the light-front time-reversal condition. We make some comments on the consequences of the angular condition for the analysis of the high-$Q^2$ deuteron electromagnetic form factors, and we further apply the general angular condition to the electromagnetic transition between spin-1/2 and spin-3/2 systems and find a relation useful for the analysis of the N-$\Delta$ transition form factors. We also discuss the scaling law and the subleading power corrections in the Breit and light-front frames.Comment: 24 pages,2 figure

Novel Structure Function for Photon Fragmentation into a Λ\Lambda Hyperon and Transverse Λ\Lambda Polarization in Unpolarized Electron-Positron Annihilation

The possibility is examined for the inclusive $\Lambda$ in unpolarized electron-positron annihilation to be transversely polarized. Due to final-state interactions, there exists a novel structure function $\hat F(z,Q^2)$ for the inclusive $\Lambda$ hyperon (or any other baryons) production from the unpolarized time-like photon fragmentation, which makes contribution to the transverse $\Lambda$ polarization in the unpolarized electron-positron annihilation.Comment: RevTex, 4 pages, the version appearing in Phys. Rev.