2,539 research outputs found
B-L-violating Masses in Softly Broken Supersymmetry
We prove a general low-energy theorem establishing a generic relation between
the neutrino Majorana mass and the superpartner sneutrino B-L-violating
"Majorana"-like mass term. The theorem states that, if one of these two
quantities is non-zero the other one is also non-zero and, vice versa, if one
of them vanishes the other vanishes, too. The theorem is a consequence of the
underlying supersymmetry (SUSY) and valid for any realistic gauge model with
weak scale softly broken SUSY.Comment: 7 pages, Latex, 1 Postscript figur
Modified Paschos-Wolfenstein relation and extraction of weak mixing angle sin^2 theta_W
The NuTeV collaboration reported anomalously large weak mixing angle sin^2
theta_W in comparison with the standard model prediction. Neutrino and
antineutrino charged- and neutral-current events are analyzed for extracting
sin^2 theta_W. Although the Paschos-Wolfenstein relation is not directly used
in the analysis, it plays an important role in the determination. Noting that
the target nucleus, iron, is not an isoscalar nucleus, we derive a
leading-order expression for a modified Paschos-Wolfenstein relation for
nuclei, which may have neutron excess. Then, using charge and baryon-number
conservations for nuclei, we discuss a nuclear correction in the sin^2 theta_W
determination. It is noteworthy that nuclear modifications are different
between valence up- and down-quark distributions. We show this difference
effect on the NuTeV sin^2 theta_W deviation.Comment: 5 pages, REVTeX4.0, revtex4.cls, url.sty, natbib.sty, revsymb.sty,
10pt.rtx, aps.rtx, amssymb.sty, amsfonts.sty, 3 eps figures. Phys. Rev. D in
press. Email: [email protected] See also http://hs.phys.saga-u.ac.j
Interpretations of the NuTeV
We summarize theoretical explanations of the three discrepancy
between measured by NuTeV and predicted by the Standard Model
global fit. Possible new physics explanations ({\it e.g.} an unmized ) are
not compelling. The discrepancy would be reduced by a positive momentum
asymmetry in the strange sea; present experimental estimates of are
unreliable or incomplete. Upgrading the NuTeV analysis to NLO would alleviate
concerns that the discrepancy is a QCD effect.Comment: (proceedings for the NuFact'02 Workshop); reference and footnote
added, following the NuTeV proceeding
Lie symmetries of nonlinear boundary value problems
Nonlinear boundary value problems (BVPs) by means of the classical Lie
symmetry method are studied. A new definition of Lie invariance for BVPs is
proposed by the generalization of existing those on much wider class of BVPs. A
class of two-dimensional nonlinear boundary value problems, modeling the
process of melting and evaporation of metals, is studied in details. Using the
definition proposed, all possible Lie symmetries and the relevant reductions
(with physical meaning) to BVPs for ordinary differential equations are
constructed. An example how to construct exact solution of the problem with
correctly-specified coefficients is presented and compared with the results of
numerical simulations published earlier.Comment: Published versio
Dynamical Structure of Viscous Accretion Disks with Shocks
We develop and discuss global accretion solutions for viscous ADAF disks
containing centrifugally supported isothermal shock waves. The fact that such
shocks can exist at all in ADAF disks is a new result. Interestingly, we find
that isothermal shocks can form even when the level of viscous dissipation is
relatively high. In order to better understand this phenomenon, we explore all
possible combinations of the fundamental flow parameters, such as specific
energy, specific angular momentum, and viscosity, to obtain the complete family
of global solutions. This procedure allows us to identify the region of the
parameter space where isothermal shocks can exist in viscous ADAF disks. The
allowed region is maximized in the inviscid case, and it shrinks as the level
of viscous dissipation increases. Adopting the canonical value gamma=1.5 for
the ratio of specific heats, we find that the shock region disappears
completely when the Shakura-Sunyaev viscosity parameter alpha exceeds the
critical value ~0.27. This establishes for the first time that steady ADAF
disks containing shocks can exist even for relatively high levels of viscous
dissipation. If an isothermal shock is present in the disk, it would have
important implications for the acceleration of energetic particles that can
escape to power the relativistic jets commonly observed around underfed,
radio-loud black holes. In two specific applications, we confirm that the
kinetic luminosity lost from the disk at the isothermal shock location is
sufficient to power the observed relativistic outflows in M87 and Sgr A*.Comment: accepted by Ap
Effect of Asymmetric Strange-Antistrange Sea to the NuTeV Anomaly
We calculate the strange quark and antiquark distributions of the nucleon by
using the effective chiral quark model, and find that the strange-antistrange
asymmetry can bring a contribution of about 60--100% to the NuTeV deviation of
from the standard value measured in other electroweak
processes. The results are insensitive to different inputs. The light-flavor
quark asymmetry of is also investigated and found to be
consistent with the experimental measurements. Therefore the chiral quark model
provides a successful picture to understand the NuTeV anomaly, as well as the
light-flavor quark asymmetry and the proton spin problem in previous studies.Comment: 10 LaTeX pages, 2 figures, Version to appear in PL
On the Lp-theory of C0-semigroups associated with second-order elliptic operators with complex singular coefficients
A work in Perturbation Theory, with a purpose to consider well-posedness of elliptic and parabolic PDE with singular complex coefficient
The NuTeV Anomaly, Neutrino Mixing, and a Heavy Higgs Boson
Recent results from the NuTeV experiment at Fermilab and the deviation of the
Z invisible width, measured at LEP/SLC, from its Standard Model (SM) prediction
suggest the suppression of neutrino-Z couplings. Such suppressions occur
naturally in models which mix the neutrinos with heavy gauge singlet states. We
postulate a universal suppression of the Z-nu-nu couplings by a factor of
(1-epsilon) and perform a fit to the Z-pole and NuTeV observables with epsilon
and the oblique correction parameters S and T. Compared to a fit with S and T
only, inclusion of epsilon leads to a dramatic improvement in the quality of
the fit. The values of S and T preferred by the fit can be obtained within the
SM by a simple increase in the Higgs boson mass. However, if the W mass is also
included in the fit, a non-zero U parameter becomes necessary which cannot be
supplied within the SM. The preferred value of epsilon suggests that the seesaw
mechanism may not be the reason why neutrinos are so light.Comment: 19 pages, REVTeX4, 8 postscript figures. Updated references. Typos
correcte
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