15,660 research outputs found
U-Spin Tests of the Standard Model and New Physics
Within the standard model, a relation involving branching ratios and direct
CP asymmetries holds for the B-decay pairs that are related by U-spin. The
violation of this relation indicates new physics (NP). In this paper, we assume
that the NP affects only the Delta S = 1 decays, and show that the NP operators
are generally the same as those appearing in B -> pi K decays. The fit to the
latest B -> pi K data shows that only one NP operator is sizeable. As a
consequence, the relation is expected to be violated for only one decay pair:
Bd -> K0 pi0 and Bs -> Kbar0 pi0.Comment: 12 pages, latex, no figures. References changed to follow MPL
guidelines; info added about U-spin breaking and small NP strong phases;
discussion added about final-state pi-K rescattering; analysis and
conclusions unaltere
Universal law for waiting internal time in seismicity and its implication to earthquake network
In their paper (Europhys. Lett., 71 (2005) 1036), Carbone, Sorriso-Valvo,
Harabaglia and Guerra showed that "unified scaling law" for conventional
waiting times of earthquakes claimed by Bak et al. (Phys. Rev. Lett., 88 (2002)
178501) is actually not universal. Here, instead of the conventional time, the
concept of the internal time termed the event time is considered for
seismicity. It is shown that, in contrast to the conventional waiting time, the
waiting event time obeys a power law. This implies the existence of temporal
long-range correlations in terms of the event time with no sharp decay of the
crossover type. The discovered power-law waiting event-time distribution turns
out to be universal in the sense that it takes the same form for seismicities
in California, Japan and Iran. In particular, the parameters contained in the
distribution take the common values in all these geographical regions. An
implication of this result to the procedure of constructing earthquake networks
is discussed.Comment: 21 pages, 5 figure
Radiative penguin Bs decays at Belle
We report searches for the radiative penguin decays Bs to phi gamma and Bs to
gamma gamma based on a 23.6 fb-1 data sample collected with the Belle detector
at the KEKB e+e- energy-asymmetric collider operating at the Upsilon(5S)
resonance.Comment: On behalf of the Belle Collaboration. To appear in the proceedings of
the International Europhysics Conference on High Energy Physics
(EPS-HEP2007), Manchester, England, 19-25 July 2007. 3 pages, 2 figure
Microcanonical Foundation for Systems with Power-Law Distributions
Starting from microcanonical basis with the principle of equal a priori
probability, it is found that, besides ordinary Boltzmann-Gibbs theory with the
exponential distribution, a theory describing systems with power-law
distributions can also be derived.Comment: 9 page
Supersymmetry breaking in a warped slice with Majorana-type masses
We study the five-dimensional (5D) supergravity compactified on an orbifold
S^1/Z_2, where the U(1)_R symmetry is gauged by the graviphoton with Z_2-even
coupling. In contrast to the case of gauging with Z_2-odd coupling, this class
of models has Majorana-type masses and allows the Scherk-Schwarz (SS) twist
even in the warped spacetime. Starting from the off-shell formulation, we show
that the supersymmetry is always broken in an orbifold slice of AdS_5,
irrespective of the value of the SS twist parameter. We analyze the spectra of
gaugino and gravitino in such background, and find the SS twist can provide
sizable effects on them in the small warping region.Comment: 1+20 pages, 6 figure
Analysis of the Fusion Hindrance in Mass-symmetric Heavy Ion Reactions
The fusion hindrance, which is also denominated by the term extra-push, is
studied on mass-symmetric systems by the use of the liquid drop model with the
two-center parameterization. Following the idea that the fusion hindrance
exists only if the liquid drop barrier (saddle point) is located at the inner
side of the contact point after overcoming the outer Coulomb barrier, the
reactions in which two barriers are overlapped with each other are determined.
It is shown that there are many systems where the fusion hindrance does not
exist for the atomic number of projectile or target nucleus , while
for , all of the mass-symmetric reactions are fusion-hindered.Comment: 6 pages, 4 figures. to be published in Sci. in China
Gauged Symmetries and Fayet-Iliopoulos Terms in 5D Orbifold Supergravity
We discuss a gauged supergravity on five-dimensional (5D) orbifold
() in which both a -even U(1) gauge field and the -odd
graviphoton take part in the gauging. Based on the off-shell
formulation of 5D supergravity, we analyze the structure of Fayet-Iliopoulos
(FI) terms allowed in such model. Introducing a -even gauge field
accompanies new bulk and boundary FI terms in addition to the known integrable
boundary FI term which could be present in the absence of any gauged
symmetry. Some physical consequences of these new FI terms are examined.Comment: 1+17 pages, 9 figures, typeset in JHEP styl
The XYZs of Charmonium at BES
This contribution reviews some recent developments in charmonium
spectroscopy, and discusses related theoretical predictions. The spectrum of
states, strong decays of states above open charm threshold, electromagnetic
transitions, and issues related to the recent discoveries of the "XYZ" states
are discussed. Contributions that BES can make to our understanding of
charmonium and related states are stressed in particular.Comment: 5 pages, 1 eps figure. Invited contribution to the International
Workshop on Tau-Charm Physics Charm2006 (5-7 June 2006, Beijing, China
Nondecoupling of Heavy Fermions and a Special Yukawa Texture
Talk based on work entitled ``Yukawa textures, new physics and
nondecoupling,'' done in collaboration with G. C. Branco and J. I.
Silva-Marcos, arXiv:hep-ph/0612252, to appear in Phys. Rev. D. In this work we
pointed out that New Physics can play an important r\^ ole in rescuing some of
the Yukawa texture zero ans\" atze which would otherwise be eliminated by the
recent, more precise measurements of . We have shown that the presence
of an isosinglet vector-like quark which mixes with standard quarks, can render
viable a particularly interesting four texture zero Yukawa ansatz. The crucial
point is the nondecoupling of the effects of the isosinglet quark, even for
arbitrary large values of its mass.Comment: Invited talk at CTP Symposium on Supersymmetry at LHC: Theoretical
and Experimental Prospectives, Cairo, Egypt, 11-14 Mar 200
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