250 research outputs found
Logarithmic Corrections to N=2 Black Hole Entropy: An Infrared Window into the Microstates
Logarithmic corrections to the extremal black hole entropy can be computed
purely in terms of the low energy data -- the spectrum of massless fields and
their interaction. The demand of reproducing these corrections provides a
strong constraint on any microscopic theory of quantum gravity that attempts to
explain the black hole entropy. Using quantum entropy function formalism we
compute logarithmic corrections to the entropy of half BPS black holes in N=2
supersymmetric string theories. Our results allow us to test various proposals
for the measure in the OSV formula, and we find agreement with the measure
proposed by Denef and Moore if we assume their result to be valid at weak
topological string coupling. Our analysis also gives the logarithmic
corrections to the entropy of extremal Reissner-Nordstrom black holes in
ordinary Einstein-Maxwell theory.Comment: LaTeX file, 66 page
Observation of the and the Y(2175) in
The cross sections for and e^+ e^- \to \phi
\fzero are measured from threshold to using
initial state radiation. The analysis is based on a data sample of 673
fb collected on and below the resonance with the Belle
detector at the KEKB asymmetric-energy collider. First measurements
are reported for the resonance parameters of the in the
mode: MeV/ and MeV/. A structure at ,
corresponding to the so called Y(2175), is observed; its mass and width are
determined to be MeV/ and , respectively.Comment: 11 pages, 6 figures. Add one plot. Accepted by Phys.Rev.D(RC
A Low-Footprint Java-to-Native Compilation Scheme Using Formal Methods
Ahead-of-Time and Just-in-Time compilation are common ways to improve runtime performances of restrained systems like Java Card by turning critical Java methods into native code. However, native code is much bigger than Java bytecode, which severely limits or even forbids these practices for devices with memory constraints. In this paper, we describe and evaluate a method for reducing natively-compiled code by suppressing runtime exception check sites, which are emitted when compiling bytecodes that may potentially throw runtime exceptions. This is made possible by completing the Java program with JML annotations, and using a theorem prover in order to formally prove that the compiled methods never throw runtime exceptions. Runtime exception check sites can then safely be removed from the generated native code, as it is proved they will never be entered. We have experimented our approach on several card-range and embedded Java applications, and were able to remove almost all the exception check sites. Results show memory footprints for native code that are up to 70% smaller than the non-optimized version, and sometimes as low than 115% the size of the Java bytecode when compiled for ARM thumb
Observation of B_s0->D_s*- pi+, B_s0->D_s(*)- rho+ Decays and Measurement of B_s0->D_s*- rho+ Polarization
First observations of the B_s0->D_s*- pi+, B_s0->D_s- rho+ and B_s0->D_s*-
rho+ decays are reported together with measurements of their branching
fractions: B(B_s0->D_s*- pi+)=(2.4 +0.5-0.4(stat.) +-0.3(syst.)
+-0.4(fs))x10^(-3), B(Bs->D_s- rho+)=(8.5 +1.3-1.2(stat.) +-1.1(syst.)
+-1.3(fs))x10^(-3) and B(Bs->D_s*- rho+)=(11.8 +2.2-2.0(stat.) +-1.7(syst.)
+-1.8(fs))x10^(-3) (f_s=N(B_s(*)B_s(*)-bar)/N(b b-bar)). From helicity-angle
distributions, we measured the longitudinal polarization fraction in
B_s0->D_s*- rho+ decays to be f_L(Bs->D_s*- rho+)=1.05 +0.08-0.10(stat.)
+0.03-0.04(syst.). These results are based on a 23.6 /fb data sample collected
at the Y(5S) resonance with the Belle detector at the KEKB e+e- collider.Comment: 6 pages, 2 figures; submitted to Phys. Rev. Lett
Search for Lepton-Flavor-Violating and Lepton-Number-Violating tau to lhh' Decay Modes
We search for lepton-flavor-violating and lepton-number-violating tau decays
into a lepton (l = electron or muon) and two charged mesons (h, h' = pion or
Kaon) using 854 fb^{-1} of data collected with the Belle detector at the KEKB
asymmetric-energy e^+e^- collider. We obtain 90% confidence level upper limits
on the tau to lhh' branching fractions in the range (2.0-8.4)*10^{-8}. These
results improve upon our previously published upper limits by factors of about
1.8 on average.Comment: 14 pages, 5 figures, submitted to Phys. Lett.
Study of B^{+-} -> K^{+-}(K_S K pi)^0 Decay and Determination of eta_c and eta_c(2S) Parameters
We report the results of a study of and
decays followed by and
decays to . The results are obtained from a data sample containing
535 million -meson pairs collected by the Belle experiment at the
KEKB collider. We measure the products of the branching fractions
and . Interference with the non-resonant component leads to significant
model uncertainty in the measurement of these product branching fractions. Our
analysis accounts for this interference and allows the model uncertainty to be
reduced. We also obtain the following charmonia masses and widths:
MeV/,
MeV/,
MeV/,
MeV/.Comment: 23 pages, 10 figures, submitted to PL
Search for Lepton-Flavor-Violating tau Decays into a Lepton and a Vector Meson
We search for lepton-flavor-violating tau-> ell V^0 decays, where ell is an
electron or muon and V^0 is one of the vector mesons rho^0, phi, omega, K*0 and
K*0-bar. We use 854 fb^{-1} of data collected with the Belle detector at the
KEKB asymmetric-energy e^+e^- collider. No evidence for a signal is found in
any decay mode, and we obtain 90% confidence level upper limits on the
individual branching fractions in the range (1.2-8.4)*10^{-8}.Comment: 13 pages, 5 figures, submitted to Phys. Lett.
Search for the Chiral Magnetic Effect in Au+Au collisions at GeV with the STAR forward Event Plane Detectors
A decisive experimental test of the Chiral Magnetic Effect (CME) is
considered one of the major scientific goals at the Relativistic Heavy-Ion
Collider (RHIC) towards understanding the nontrivial topological fluctuations
of the Quantum Chromodynamics vacuum. In heavy-ion collisions, the CME is
expected to result in a charge separation phenomenon across the reaction plane,
whose strength could be strongly energy dependent. The previous CME searches
have been focused on top RHIC energy collisions. In this Letter, we present a
low energy search for the CME in Au+Au collisions at
GeV. We measure elliptic flow scaled charge-dependent correlators relative to
the event planes that are defined at both mid-rapidity and at
forward rapidity . We compare the results based on the
directed flow plane () at forward rapidity and the elliptic flow plane
() at both central and forward rapidity. The CME scenario is expected
to result in a larger correlation relative to than to , while
a flow driven background scenario would lead to a consistent result for both
event planes[1,2]. In 10-50\% centrality, results using three different event
planes are found to be consistent within experimental uncertainties, suggesting
a flow driven background scenario dominating the measurement. We obtain an
upper limit on the deviation from a flow driven background scenario at the 95\%
confidence level. This work opens up a possible road map towards future CME
search with the high statistics data from the RHIC Beam Energy Scan Phase-II.Comment: main: 8 pages, 5 figures; supplementary material: 2 pages, 1 figur
Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV
Peer reviewe
Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV
Peer reviewe
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