29,671 research outputs found
Pulsar Velocity with Three-Neutrino Oscillations in Non-adiabatic Processes
We have studied the position dependence of neutrino energy on the
Kusenko-Segr\`{e} mechanism as an explanation of the proper motion of pulsars.
The mechanism is also examined in three-generation mixing of neutrinos and in a
non-adiabatic case. The position dependence of neutrino energy requires the
higher value of magnetic field such as Gauss in order
to explain the observed proper motion of pulsars. It is shown that possible
non-adiabatic processes decrease the neutrino momentum asymmetry, whereas an
excess of electron neutrino flux over other flavor neutrino fluxes increases
the neutrino momentum asymmetry. It is also shown that a general treatment with
all three neutrinos does not modify the result of the two generation treatment
if the standard neutrino mass hierarchy is assumed.Comment: 8 pages, REVTEX, no figure
A probe of the Radion-Higgs mixing in the Randall-Sundrum model at e^+ e^- colliders
In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by
the effective electroweak scale. A novel feature of the existence of
gravity-scalar mixing would be a sizable three-point vertex among the KK
graviton, Higgs and radion. We study this vertex in the process e^+ e^- -> h
phi, which is allowed only with a non-zero radion-Higgs mixing. It is shown
that the angular distribution is a unique characteristic of the exchange of
massive spin-2 gravitons, and the total cross section at the future e^+ e^-
collider is big enough to cover a large portion of the parameter space where
the LEP/LEP II data cannot constrain.Comment: 14pages, RevTeX, 5 figure
Custodial bulk Randall-Sundrum model and B->K* l+ l'-
The custodial Randall-Sundrum model based on SU(2)_L X SU(2)_R X U(1)_(B-L)
generates new flavor-changing-neutral-current (FCNC) phenomena at tree level,
mediated by Kaluza-Klein neutral gauge bosons. Based on two natural assumptions
of universal 5D Yukawa couplings and no-cancellation in explaining the observed
standard model fermion mixing matrices, we determine the bulk Dirac mass
parameters. Phenomenological constraints from lepton-flavor-violations are also
used to specify the model. From the comprehensive study of B->K* l+ l'-, we
found that only the B->K*ee decay has sizable new physics effects. The zero
value position of the forward-backward asymmetry in this model is also
evaluated, with about 5% deviation from the SM result. Other effective
observables are also suggested such as the ratio of two differential (or
partially integrated) decay rates of B->K*ee and B->K*mu mu. For the first KK
gauge boson mass of M_A^(1)=2-4 TeV, we can have about 10-20% deviation from
the SM results.Comment: references added with minor change
Associated production of a single heavy T-quark in the littlest and simplest little Higgs models
The colored SU(2)-singlet heavy T-quark is one of the most crucial
ingredients in little Higgs models, which is introduced to cancel the largest
contribution of the SM top quark to the Higgs boson mass at one-loop level. In
two representative little Higgs models, the littlest Higgs model and the SU(3)
simplest Higgs model, we comprehensively study the single heavy T-quark
production at Large Hadron Collider (LHC). After presenting the possibility of
relatively light (~500 GeV) T-quark in the simplest little Higgs model, we
consider all the relevant processes, the 2->2 process of qb->q'T, the 2->3
process of qg->q'Tb, the s-channel process of q bar(q)'->T bar{b}, and the
gluon fusion process of gg->T bar{t}. We found that the 2->3 process can be
quite important, as its cross section is about 30% of the 2->2 one and it is
dominant in high p_T distributions. The s-channel and the gluon fusion
processes also show distinctive features in spite of their suppressed cross
sections. In the gluon fusion process of the simplest little Higgs model, for
example, the pseudo-scalar contribution is rather dominant over the Higgs
contribution for relatively light M_T.Comment: 27 pages, using RevTeX; references adde
Electron Removal Self Energy and its application to Ca2CuO2Cl2
We propose using the self energy defined for the electron removal Green's
function. Starting from the electron removal Green's function, we obtained
expressions for the removal self energy Sigma^ER (k,omega) that are applicable
for non-quasiparticle photoemission spectral functions from a single band
system. Our method does not assume momentum independence and produces the self
energy in the full k-omega space. The method is applied to the angle resolved
photoemission from Ca_2CuO_2Cl_2 and the result is found to be compatible with
the self energy value from the peak width of sharp features. The self energy is
found to be only weakly k-dependent. In addition, the Im Sigma shows a maximum
at around 1 eV where the high energy kink is located.Comment: 5 pages, 3 figure
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