18,574 research outputs found

    Brief Report from the Tevatron

    Full text link
    We report on the B physics prospects from the Fermilab Tevatron, summarizing the B physics goals of the CDF and DO experiments using their upgraded detectors. We discuss the time schedule for completion of the detector upgrades and summarize the current measurement of the CP violation parameter sin(2 beta) at CDF.Comment: Final version as it will appear in Proceedings of XIX International Symposium on Lepton and Photon Interactions at High Energies, Stanford University, August 9-14, 1999. 8 pages plus title page; 5 figure

    Measurements of Diffractive Processes at CDF

    Full text link
    We review the results of measurements on hard diffractive processes performed by the CDF Collaboration and report preliminary CDF results on two soft diffractive processes with a leading antiproton and a rapidity gap in addition to that associated with the antiproton. All results have been obtained from data collected in Run I of the Fermilab Tevatron pˉp\bar pp collider.Comment: 7 pages, Presented at 14th^{th} Topical Conference on Hadron Collider Physics, HCP-2002, Karlsruhe, Germany, 29 Sep - 4 Oct 200

    Nonextensive thermodynamic relations

    Full text link
    The generalized zeroth law of thermodynamics indicates that the physical temperature in nonextensive statistical mechanics is different from the inverse of the Lagrange multiplier, beta. This leads to modifications of some of thermodynamic relations for nonextensive systems. Here, taking the first law of thermodynamics and the Legendre transform structure as the basic premises, it is found that Clausius definition of the thermodynamic entropy has to be appropriately modified, and accordingly the thermodynamic relations proposed by Tsallis, Mendes and Plastino [Physica A 261 (1998) 534] are also to be rectified. It is shown that the definition of specific heat and the equation of state remain form invariant. As an application, the classical gas model is reexamined and, in marked contrast with the previous result obtained by Abe [Phys. Lett. A 263 (1999) 424: Erratum A 267 (2000) 456] using the unphysical temperature and the unphysical pressure, the specific heat and the equation of state are found to be similar to those in ordinary extensive thermodynamics.Comment: 17 pages. The discussion about the Legendre transform structure is modified and some additional comments are mad

    Energy Level Diagrams for Black Hole Orbits

    Full text link
    A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy to atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy, and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.Comment: 8 page

    About the modern "experimental value" of W boson width.

    Get PDF
    It is shown that the methods which have been used up to now to determine the WW width from the ppˉp\bar p data confirm the SM predictions for some combinations of various phenomenological parameters, however, they do not give an independent value for the WW width. Moreover, the accuracy that could be achieved in future experimental checks of SM predictions for such quantities is limited by effects which require detailed theoretical study.Comment: Latex, 8 pages

    Aftershocks in Modern Perspectives: Complex Earthquake Network, Aging, and Non-Markovianity

    Full text link
    The phenomenon of aftershocks is studied in view of science of complexity. In particular, three different concepts are examined: (i) the complex-network representation of seismicity, (ii) the event-event correlations, and (iii) the effects of long-range memory. Regarding (i), it is shown the clustering coefficient of the complex earthquake network exhibits a peculiar behavior at and after main shocks. Regarding (ii), it is found that aftershocks experience aging, and the associated scaling holds. And regarding (iii), the scaling relation to be satisfied by a class of singular Markovian processes is violated, implying the existence of the long-range memory in processes of aftershocks.Comment: 28 pages, 6 figures and 1 table. Acta Geophysica, in pres

    The Rare Top Decays tbW+Zt \to b W^+ Z and tcW+Wt \to c W^+ W^-

    Full text link
    The large value of the top quark mass implies that the rare top decays tbW+Z,sW+Zt \rightarrow b W^+ Z, s W^+ Z and dW+Zd W^+ Z, and tcW+Wt \rightarrow c W^+ W^- and uW+Wu W^+ W^-, are kinematically allowed decays so long as mtmW+mZ+mdi171.5GeV+mdim_t \ge m_W + m_Z + m_{d_i} \approx 171.5 GeV + m_{d_i} or mt2mW+mu,c160.6GeV+mu,cm_t \ge 2m_W + m_{u,c} \approx 160.6 GeV + m_{u,c}, respectively. The partial decay widths for these decay modes are calculated in the standard model. The partial widths depend sensitively on the precise value of the top quark mass. The branching ratio for tbW+Zt\rightarrow b W^+ Z is as much as 2×1052 \times 10^{-5} for mt=200GeVm_t = 200 GeV, and could be observable at LHC. The rare decay modes tcW+Wt \rightarrow c W^+ W^- and uW+Wu W^+ W^- are highly GIM-suppressed, and thus provide a means for testing the GIM mechanism for three generations of quarks in the u, c, t sector.Comment: 19 pages, latex, t->bWZ corrected, previous literature on t->bWZ cited, t->cWW unchange

    On Observing Top Quark Production at the Tevatron

    Full text link
    A technique for separating top quark production from Standard Model background events is introduced. It is applicable to the channel in which one top quark decays semi-leptonically and its anti-quark decays hadronically into three jets, or vice versa. The method is shown to discriminate dramatically between Monte Carlo generated events with and without simulated top quarks of mass around 120 GeV and above. The simulations were performed with CDF detector characteristics incorporated, showing that the method is applicable to existing data.Comment: 8 pages, TUFTS-TH-92-G01 (Two minor TeX mistakes corrected

    Information measures based on Tsallis' entropy and geometric considerations for thermodynamic systems

    Full text link
    An analysis of the thermodynamic behavior of quantum systems can be performed from a geometrical perspective investigating the structure of the state space. We have developed such an analysis for nonextensive thermostatistical frameworks, making use of the q-divergence derived from Tsallis' entropy. Generalized expressions for operator variance and covariance are considered, in terms of which the fundamental tensor is given.Comment: contribution to 3rd NEXT-SigmaPhi International Conference (August 2005, Kolymbari, Greece