18,574 research outputs found

### Brief Report from the Tevatron

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

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 $\bar pp$ collider.Comment: 7 pages, Presented at 14$^{th}$ Topical Conference on Hadron Collider
Physics, HCP-2002, Karlsruhe, Germany, 29 Sep - 4 Oct 200

### Nonextensive thermodynamic relations

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

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.

It is shown that the methods which have been used up to now to determine the
$W$ width from the $p\bar p$ data confirm the SM predictions for some
combinations of various phenomenological parameters, however, they do not give
an independent value for the $W$ 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

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 $t \to b W^+ Z$ and $t \to c W^+ W^-$

The large value of the top quark mass implies that the rare top decays $t
\rightarrow b W^+ Z, s W^+ Z$ and $d W^+ Z$, and $t \rightarrow c W^+ W^-$ and
$u W^+ W^-$, are kinematically allowed decays so long as $m_t \ge m_W + m_Z +
m_{d_i} \approx 171.5 GeV + m_{d_i}$ or $m_t \ge 2m_W + m_{u,c} \approx 160.6
GeV + m_{u,c}$, 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 $t\rightarrow
b W^+ Z$ is as much as $2 \times 10^{-5}$ for $m_t = 200 GeV$, and could be
observable at LHC. The rare decay modes $t \rightarrow c W^+ W^-$ and $u W^+
W^-$ 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

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

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

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