New Types of Thermodynamics from (1+1)(1+1)-Dimensional Black Holes

For normal thermodynamic systems superadditivity $\S$, homogeneity \H and concavity \C of the entropy hold, whereas for $(3+1)$-dimensional black holes the latter two properties are violated. We show that $(1+1)$-dimensional black holes exhibit qualitatively new types of thermodynamic behaviour, discussed here for the first time, in which \C always holds, \H is always violated and $\S$ may or may not be violated, depending of the magnitude of the black hole mass. Hence it is now seen that neither superadditivity nor concavity encapsulate the meaning of the second law in all situations.Comment: WATPHYS-TH93/05, Latex, 10 pgs. 1 figure (available on request), to appear in Class. Quant. Gra

Discovering New Physics in the Decays of Black Holes

If the scale of quantum gravity is near a TeV, the LHC will be producing one black hole (BH) about every second, thus qualifying as a BH factory. With the Hawking temperature of a few hundred GeV, these rapidly evaporating BHs may produce new, undiscovered particles with masses ~100 GeV. The probability of producing a heavy particle in the decay depends on its mass only weakly, in contrast with the exponentially suppressed direct production. Furthemore, BH decays with at least one prompt charged lepton or photon correspond to the final states with low background. Using the Higgs boson as an example, we show that it may be found at the LHC on the first day of its operation, even with incomplete detectors.Comment: 4 pages, 3 figure

Estimate of B(K -> pi nu nubar) from Standard Model fits to lambda_t

We estimate B(K -> pi nu nubar) in the context of the Standard Model by fitting for lambda_t = Vtd x V*ts of the `kaon unitarity triangle' relation. We fit data from epsilon_K, the CP-violating parameter describing K-mixing, and a_{psi K}, the CP-violating asymmetry in B -> J/psi K decays. Our estimate is independent of the CKM matrix element Vcb and of the ratio of Bs to Bd mixing frequencies. The measured value of B(K+ -> pi+ nu nubar) can be compared both to this estimate and to predictions made from the ratio of B mixing frequencies.Comment: 8 pages, including 6 figures. v3 includes an expanded discussion of correlations between SM inputs to the lambda_t fit, clarifies the discussion of the independence of this result from the ratio of B mixing frequencies, includes minor updates to the values of SM input parameters, and includes some new and some updated reference

Searching for family-number conserving neutral gauge bosons from extra dimensions

Previous studies have shown how the three generations of the Standard Model fermions can arise from a single generation in more than four dimensions, and how off-diagonal neutral couplings arise for gauge-boson Kaluza-Klein recurrences. These couplings conserve family number in the leading approximation. While an existing example, built on a spherical geometry, suggests a high compactification scale, we conjecture that the overall structure is generic, and work out possible signatures at colliders, compatible with rare decays data.Comment: 4 pages, 2 figures, jetpl.cls style, references adde

Two-parameter deformations of logarithm, exponential, and entropy: A consistent framework for generalized statistical mechanics

A consistent generalization of statistical mechanics is obtained by applying the maximum entropy principle to a trace-form entropy and by requiring that physically motivated mathematical properties are preserved. The emerging differential-functional equation yields a two-parameter class of generalized logarithms, from which entropies and power-law distributions follow: these distributions could be relevant in many anomalous systems. Within the specified range of parameters, these entropies possess positivity, continuity, symmetry, expansibility, decisivity, maximality, concavity, and are Lesche stable. The Boltzmann-Shannon entropy and some one parameter generalized entropies already known belong to this class. These entropies and their distribution functions are compared, and the corresponding deformed algebras are discussed.Comment: Version to appear in PRE: about 20% shorter, references updated, 13 PRE pages, 3 figure

Role of five-quark components in radiative and strong decays of the Lambda(1405) resonance

Within an extended chiral constituent quark model, three- and five-quark structure of the $S_{01}$ resonance $\Lambda(1405)$ is investigated. Helicity amplitudes for the electromagnetic decays ($\Lambda(1405) \to \Lambda(1116)\gamma$, $\Sigma(1194)\gamma$), and transition amplitudes for strong decays ($\Lambda(1405)\to\Sigma(1194)\pi$, $K^{-}p$) are drived, as well as the relevant decay widths. The experimental value for the strong decay width, $\Gamma_{\Lambda(1405)\to (\Sigma \pi)^\circ}=50\pm 2$ MeV, is well reproduced with about 50% of five-quark admixture in the $\Lambda(1405)$. Important effects due to the configuration mixings among $\Lambda^{2}_{1}P_{A}$, $\Lambda^{2}_{8}P_{M}$ and $\Lambda^{4}_{8}P_{M}$ are found. In addition, transitions between the three- and five-quark components in the baryons turn out to be significant in both radiative and strong decays of the $\Lambda(1405)$ resonance.Comment: typos and numerical mistakes corrected, to appear in Phys. Rev.

Is it still worth searching for lepton flavor violation in rare kaon decays?

Prospective searches for lepton flavor violation (LFV) in rare kaon decays at the existing and future intermediate-energy accelerators are considered. The proposed studies are complementary to LFV searches in muon-decay experiments and offer a unique opportunity to probe models with approximately conserved fermion-generation quantum number with sensitivity superior to that in other processes. Consequently, new searches for LFV in kaon decays are an important and independent part of the general program of searches for lepton flavor violation in the final states with charged leptons.Comment: 30 pages, 10 figures. An extended version of the talk given at the Chicago Flavor Seminar, February 27, 2004. In the new version some misprints were corrected and some new data for LFV-processes were added. The main content of the paper was not changed. The paper is published in Yad. Fiz. 68, 1272 (2005