102 research outputs found
Supersymmetric Time Reversal Violation in Semileptonic Decays of Charged Mesons
We provide a general analysis of time reversal violation arising from
misalignment between quark and squark mass eigenstates. In particular, we focus
on the possibility of large enhancement effects due to the top quark mass. For
semileptonic decays of the charged mesons, , , and , the transverse polarization of
the lepton is a -odd observable that is of great experimental
interest. It is noted that under favorable choice of parameters,
in decay can be detectable at the ongoing KEK
experiment and it holds a promising prospect for discovery at the proposed BNL
experiment. Furthermore, in decay could well be
within the reach of factories, but in decay is
not large enough for detection at the proposed -charm factory.Comment: LaTex, 14 pages, 2 figures, minor changes, version to appear in Phys.
Lett.
QCD strings and the thermodynamics of the metastable phase of QCD at large
The thermodyanmics of a metastable hadronic phase of QCD at large are
related to properties of an effective QCD string. In particular, it is shown
that in the large limit and near the maximum hadronic temperature, ,
the energy density and pressure of the metastable phase scale as (for ) and (for ) where is the effective
number of transverse dimensions of the string theory. It is shown, however,
that for the thermodynamic quantities of interest the limits and
do not commute. The prospect of extracting via
lattice simulations of the metastable hadronic phase at moderately large
is discussed.Comment: After this paper was published, the author became aware of an
important early paper by Charles Thorn on the subject of the QCD phase
transition at large N_c and its relation to the Hagedorn spectrum. Given the
pioneering nature of Thorn's paper, and the fact that it is not as widely
known as it should be, it is important to cite it in the present work. This
updated version cites Thorn's wor
Effect of Low Strain Rate on Formability of Aluminium Alloy
Effect of low strain rate on formability of aluminium alloy 2014 by means of torsion test was performed. The presented experimental results exhibit decrease of the ductility with increase and decrease of ε and T, respectively, and optimal values of , ε T are thus obtained
Hadronic Vacuum Polarization Contribution to g-2 of the Leptons and alpha(M_Z)
We review and compare recent calculations of hadronic vacuum polarization
effects. In particular, we consider the anomalous magnetic moments g-2 of the
leptons and alpha(M_Z), the effective fine structure constant at the
Z--resonance.Comment: 11 pages, 11 postscript figures, uses espcrc2.sty. Postscript version
available at http://www.ifh.de/~fjeger/desy-96-121.ps.gz To be published in
the proceedings of Zeuthen Workshop on Elementary Particle Theory: QCD and
QED in Higher Orders, Rheinsberg, Germany, 21-26 Apr 199
The String Density of States from The Convolution Theorem
We study the microcanonical density of states and the thermal properties of a
bosonic string gas starting from a calculation of the Helmholtz free energy in
the S-representation. By adding more and more strings to the single string
system, we induce that, for infinite volume, there is no negative specific heat
region but a transition at a finite value of the energy per string from the low
energy regime to a region of infinite specific heat at the Hagedorn
temperature. Forcing the description of this phase in terms of strings gives a
picture in which there is a very fat string in a sea of low energetic ones. We
argue that the necessary changing of this description should not change the
fact that perturbatively is a maximum temperature of the system.Comment: 15 pages, LaTeX, epsf.sty and a4.sty, 5 figures in PostScrip
Lepton Polarization in the Decays and
The effective Hamiltonian for the decay predicts a
characteristic polarization for the final state lepton, which can serve as an
important test of the underlying theory. The lepton polarization has, in
addition to a longitudinal component , two orthogonal components and
, lying in and perpendicular to the decay plane which are proportional to
, and therefore significant for the channel. The normal
polarization component is a -odd effect connected with the
nonhermiticity of the effective Hamiltonian, arising mainly from
intermediate states. We calculate all three polarization components for the
decay as a function of the lepton pair mass, and find
average values = -0.63, = 0.03. By comparison,
the $\mu^-$ polarization is = -0.77, .Comment: 17 pages, LaTeX, 5 eps figures, uses epsf.sty and cite.st
Computation of the Heavy-Light Decay Constant using Non-relativistic Lattice QCD
We report results on a lattice calculation of the heavy-light meson decay
constant employing the non-relativistic QCD approach for heavy quark and Wilson
action for light quark. Simulations are carried out at on a
lattice. Signal to noise ratio for the ground state is
significantly improved compared to simulations in the static approximation,
enabling us to extract the decay constant reliably. We compute the heavy-light
decay constant for several values of heavy quark mass and estimate the
magnitude of the deviation from the heavy mass scaling law . For the meson we find MeV, while
an extrapolation to the static limit yields = MeV.Comment: 34 pages in LaTeX including 10 figures using epsf.sty,
uuencoded-gziped-shar format, HUPD-940
Testing Supersymmetry in the Associated Production of CP-odd and Charged Higgs Bosons
In the Minimal Supersymmetric Standard Model (MSSM), the masses of the
charged Higgs boson () and the CP-odd scalar () are related by
. Furthermore, because the coupling of --
is fixed by gauge interaction, the tree level production rate of depends only on one supersymmetry parameter --the
mass () of . We show that to a good approximation this conclusion also
holds at the one-loop level. Consequently, this process can be used to
distinguish MSSM from its alternatives (such as a general two-Higgs-doublet
model) by verifying the above mass relation, and to test the prediction of the
MSSM on the product of the decay branching ratios of and in terms
of only one single parameter -- .Comment: 8 pages, 2 figures, RevTe
Numerical analysis of the Higgs mass triviality bound
Previous large calculations are combined with numerical work at to
show that the Minimal Standard Model will describe physics to an accuracy of a
few percent up to energies of the order 2 to 4 times the Higgs mass, ,
only if . This bound is the result of a systematic
search in the space of dimension six operators and is expected to hold in the
{\it continuum}. Given that studying the scalar sector in isolation is already
an approximation, we believe that our result is sufficiently accurate and that
further refinements would be of progressively diminishing interest to particle
physics. Note: The full ps file of this preprint is also available via
anonymous ftp to ftp.scri.fsu.edu. To get the ps file, ftp to this address and
use for username "anonymous" and for password your name. The file is in the
directory pub/vranas (to go to that directory type: cd pub/vranas) and is
called num_hig.ps (to get it type: get num_hig.ps)Comment: 22 pages with 10 ps figures included. Tex file. FSU-SCRI-93-29,
CU-TP-590, RU-93-0
Bootstraping the QCD Critical Point
It is shown that hadronic matter formed at high temperatures, according to
the prescription of the statistical bootstrap principle, develops a critical
point at nonzero baryon chemical potential. The location of the critical point
in the phase diagram, however, depends on the detailed knowledge of the
partition function of the deconfined phase, near the critical line. In a
simplified version of the quark-gluon partition function, the resulting
location of the critical point is compared with the solutions of other
approaches and in particular with the results of lattice QCD. The proximity of
our solution to the freeze-out area in heavy-ion experiments is also discussed.Comment: 10 pages, 3 figures in 4 file
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