1,613 research outputs found

    Comments on Baryon Melting in Quark Gluon Plasma with Gluon Condensation

    Full text link
    We consider a black hole solution with a non-trivial dilaton from IIB super gravity which is expected to describe a strongly coupled hot gauge plasma with non-vanishing gluon condensation present. We construct a rotating and moving baryon to probe the screening and phases of the plasma. Melting of the baryons in hot plasma in this background had been studied previously, however, we show that baryons melt much lower temperature than has been suggested previously.Comment: 3 figures, 12 page

    μτ\mu-\tau Symmetry and Radiatively Generated Leptogenesis

    Full text link
    We consider a μτ\mu-\tau symmetry in neutrino sectors realized at GUT scale in the context of a seesaw model. In our scenario, the exact μτ\mu-\tau symmetry realized in the basis where the charged lepton and heavy Majorana neutrino mass matrices are diagonal leads to vanishing lepton asymmetries. We find that, in the minimal supersymmetric extension of the seesaw model with large tanβ\tan\beta, the renormalization group (RG) evolution from GUT scale to seesaw scale can induce a successful leptogenesis even without introducing any symmetry breaking terms by hand, whereas such RG effects lead to tiny deviations of θ23\theta_{23} and θ13\theta_{13} from π/4\pi/4 and zero, respectively. It is shown that the right amount of the baryon asymmetry ηB\eta_B can be achieved via so-called resonant leptogenesis, which can be realized at rather low seesaw scale with large tanβ\tan\beta in our scenario so that the well-known gravitino problem is safely avoided.Comment: 17 pages, 5 figures. Published in PR

    Light-cone Gauge Superstring Field Theory and Dimensional Regularization II

    Get PDF
    We propose a dimensional regularization scheme to deal with the divergences caused by colliding supercurrents inserted at the interaction points, in the light-cone gauge NSR superstring field theory. We formulate the theory in dd dimensions and define the amplitudes as analytic functions of dd. With an appropriately chosen three-string interaction term and large negative dd, the tree level amplitudes for the (NS,NS) closed strings can be recast into a BRST invariant form, using the superconformal field theory proposed in Ref.[arXiv:0911.3704]. We show that in the limit d10d \to 10 they coincide with the results of the first quantized theory. Therefore we obtain the desired results without adding any contact interaction terms to the action.Comment: 23 pages; v2: minor modifications; v3: revised argument in section 3, added appendix C, results unchanged; v4: added clarifications, two figures and a footnote; v5: minor modification

    Light-cone Gauge NSR Strings in Noncritical Dimensions II -- Ramond Sector

    Get PDF
    Light-cone gauge superstring theory in noncritical dimensions corresponds to a worldsheet theory with nonstandard longitudinal part in the conformal gauge. The longitudinal part of the worldsheet theory is a superconformal field theory called X^{\pm} CFT. We show that the X^{\pm} CFT combined with the super-reparametrization ghost system can be described by free variables. It is possible to express the correlation functions in terms of these free variables. Bosonizing the free variables, we construct the spin fields and BRST invariant vertex operators for the Ramond sector in the conformal gauge formulation. By using these vertex operators, we can rewrite the tree amplitudes of the noncritical light-cone gauge string field theory, with external lines in the (R,R) sector as well as those in the (NS,NS) sector, in a BRST invariant way.Comment: 33 pages; v2: minor modification

    Non-Abelian Discrete Flavor Symmetries on Orbifolds

    Full text link
    We study non-Abelian flavor symmetries on orbifolds, S1/Z2S^1/Z_2 and T2/Z3T^2/Z_3. Our extra dimensional models realize DND_N, Σ(2N2)\Sigma(2N^2), Δ(3N2)\Delta(3N^2) and Δ(6N2)\Delta(6N^2) including A4A_4 and S4S_4. In addition, one can also realize their subgroups such as QNQ_N, T7T_7, etc. The S3S_3 flavor symmetry can be realized on both S1/Z2S^1/Z_2 and T2/Z3T^2/Z_3 orbifolds.Comment: 16 page
    corecore