Unnamed: 0 int64 0 41k | title stringlengths 4 274 | category stringlengths 5 18 | summary stringlengths 22 3.66k | theme stringclasses 8
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7,400 | Comments on the Electroweak Phase Transition | hep-ph | We report on an investigation of various problems related to the theory of
the electroweak phase transition. This includes a determination of the nature
of the phase transition, a discussion of the possible role of higher order
radiative corrections and the theory of the formation and evolution of the
bubbles of the ne... | physics |
7,401 | A Natural Framework for Solar and 17 keV Neutrinos | hep-ph | Motivated by recent experimental claims for the existence of a 17 keV
neutrino and by the solar neutrino problem, we construct a class of models
which contain in their low-energy spectrum a single light sterile neutrino and
one or more Nambu-Goldstone bosons. In these models the required pattern of
breaking of lepton-n... | physics |
7,402 | Towards the Theory of Cosmological Phase Transitions | hep-ph | We discuss recent progress (and controversies) in the theory of finite
temperature phase transitions. This includes the structure of the effective
potential at a finite temperature, the infrared problem in quantum statistics
of gauge fields, the theory of formation of critical and subcritical bubbles
and the theory of ... | physics |
7,403 | The quest for low-energy supersymmetry and the role of high-energy $e^+e^-$ colliders | hep-ph | The motivations for low-energy supersymmetry and the main features of the
minimal supersymmetric extension of the Standard Model are reviewed. Possible
non-minimal models and the issue of gauge coupling unification are also
discussed. Theoretical results relevant for supersymmetric particle searches at
present and futu... | physics |
7,404 | Extended Color Models with a Heavy Top Quark | hep-ph | We present a class of models in which the top quark, by mixing with new
physics at a higher energy scale, is naturally heavier than the other standard
model particles. We take this new physics to be extended color. Our models
contain new particles with masses between 100 GeV and 1 TeV, some of which may
be just within ... | physics |
7,405 | Solutions to the strong CP problem in a world with gravity | hep-ph | We examine the sensitivity of several solutions of the strong-CP problem to
violations of global symmetries by Planck scale physics. We find that the
Peccei-Quinn solution is extremely sensitive to U(1)_PQ violating operators of
dimension less than 10. We construct models in which the PQ symmetry is
protected by gauge ... | physics |
7,406 | Differential Renormalization of Massive Quantum Field Theories | hep-ph | We extend the method of differential renormalization to massive quantum field
theories treating in particular $\ph4$-theory and QED. As in the massless case,
the method proves to be simple and powerful, and we are able to find, in
particular, compact explicit coordinate space expressions for the finite parts
of two not... | physics |
7,407 | Monopole annihilation at the electroweak scale---Not! | hep-ph | We examine the issue of monopole annihilation at the electroweak scale
induced by flux tube confinement, concentrating first on the simplest
possibility---one which requires no new physics beyond the standard model.
Monopoles existing at the time of the electroweak phase transition may trigger
$W$ condensation which ca... | physics |
7,408 | How Efficient Is The Langacker-Pi Mechanism of Monopole Annihilation? | hep-ph | We investigate the dynamics of monopole annihilation by the Langacker-Pi
mechanism. We find taht considerations of causality, flux-tube energetics and
the friction from Aharonov-Bohm scatteering suggest that the monopole
annihilation is most efficient if electromagnetism is spontaneously broken at
the lowest temperatur... | physics |
7,409 | Precision bounds on $m_H$ and $m_t | hep-ph | We perform a fit to precise electroweak data to determine the Higgs and top
masses. Penalty functions taking into account their production limits are
included. We find ${\displaystyle m_H=65^{+245}_{-4}\ GeV}$ and ${\displaystyle
m_t=122^{+25}_{-20}\ GeV}$. However whereas the top $\chi^2$ distribution
behaves properly... | physics |
7,410 | Comment on ``Damping of energetic gluons and quarks in high-temperature QCD'' | hep-ph | Burgess and Marini have recently pointed out that the leading contribution to
the damping rate of energetic gluons and quarks in the QCD plasma, given by
$\gamma=c g^2\ln(1/g)T$, can be obtained by simple arguments obviating the need
of a fully resummed perturbation theory as developed by Braaten and Pisarski.
Their ca... | physics |
7,411 | Spontaneous CP Violation at the Electroweak Scale | hep-ph | Utilizing results on the cosmology of anomalous discrete symmetries we show
that models of spontaneous CP violation can in principle avoid the domain wall
problem first pointed out by Zel'dovich, Kobzarev and Okun. A small but nonzero
$\theta_{QCD}$ explicitly breaks CP and can lift the degeneracy of the two CP
conjuga... | physics |
7,412 | Solar Neutrino Data and Its Implications | hep-ph | The complete and concurrent Homestake and Kamiokande solar neutrino data sets
(including backgrounds), when compared to detailed model predictions, provide
no unambiguous indication of the solution to the solar neutrino problem. All
neutrino-based solutions, including time-varying models, provide reasonable
fits to bot... | physics |
7,413 | Strings, Textures, Inflation and Spectrum Bending | hep-ph | We discuss relationship between inflation and various models of production of
density inhomogeneities due to strings, global monopoles, textures and other
topological and non-topological defects. Neither of these models leads to a
consistent cosmological theory without the help of inflation. However, each of
these mode... | physics |
7,414 | Light Spin-One Particles Imply Gauge Invariance | hep-ph | Recently, calculations which consider the implications of anomalous trilinear
gauge-boson couplings, both at tree-level and in loop-induced processes, have
been criticized on the grounds that the lagrangians employed are not \gwk gauge
invariant. We prove that, in fact, the general Lorentz-invariant and $U(1)_\em$
inva... | physics |
7,415 | Uses and Abuses of Effective Lagrangians | hep-ph | Motivated by past and recent analyses we critically re-examine the use of
effective lagrangians in the literature to constrain new physics and to
determine the `physics reach' of future experiments. We demonstrate that many
calculations, such as those involving anomalous trilinear gauge-boson
couplings, either consider... | physics |
7,416 | Multiple photon effects in fermion-(anti)fermion scattering at SSC energies | hep-ph | We use the theory of Yennie, Frautschi and Suura to realize, via Monte Carlo
methods, the process $f\,\bbbarf\to f'\,\bbbarf'+n\gamma$ at SSC and LHC
energies, where $f$ and $f'$ are quarks or leptons. QED infrared divergences
are canceled to all orders in perturbation theory. The resulting Monte Carlo
event generator,... | physics |
7,417 | Electroweak Symmetry Breaking via a Technicolor Nambu--Jona-Lasinio Model | hep-ph | We consider a theory of gauge fields and fermions which we argue gives rise
to dynamics similar to that of the Nambu--Jona-Lasinio (NJL) model when a gauge
coupling constant is appropriately fine-tuned. We discuss the application of
this model to dynamical electroweak symmetry breaking by a top-quark
condensate. In thi... | physics |
7,418 | Aspects of Two-Photon Physics at Linear e+e- Colliders | hep-ph | We discuss various reactions at future e+e- and gamma-gamma colliders
involving real (beamstrahlung or backscattered laser) or quasi--real
(bremsstrahlung) photons in the initial state and hadrons in the final state.
The production of two central jets with large pT is described in some detail;
we give distributions for... | physics |
7,419 | Test of the Dimopouos-Hall-Raby Ansatz for Fermion Mass Matrices | hep-ph | By evolution of fermion mass matrices of the Fritzsch and the Georgi-Jarlskog
forms from the supersymmetric grand unified scale, DHR obtained predictions for
the quark masses and mixings. Using Monte Carlo methods we test these
predictions against the latest determinations of the mixings, the CP-violating
parameter eps... | physics |
7,420 | Infrared Factorization, Wilson Lines and the Heavy Quark Limit | hep-ph | It is shown that, in QCD, the same universal function
$\Gamma_{cusp}(\vartheta, \alpha_\s)$ determines the infrared behaviour of the
on-shell quark form factor, the velocity-dependent anomalous dimension in the
heavy quark effective field theory (HQET) and the renormalization properties of
the vacuum averaged Wilson li... | physics |
7,421 | Testing the Higgs Sector of the Minimal Supersymmetric Standard Model at Large Hadron Colliders | hep-ph | We study the Higgs sector of the Minimal Supersymmetric Standard Model, in
the context of proton-proton collisions at LHC and SSC energies. We assume a
relatively heavy supersymmetric particle spectrum, and include recent results
on one-loop radiative corrections to Higgs-boson masses and couplings. We begin
by discuss... | physics |
7,422 | Phenomenology of R-Parity Breaking in E6 Models | hep-ph | We explore the phenomenology of new R-parity violating operators that can
occur in E6 models. The set of allowed operators is found to depend sensitively
on the nature of the extension of the standard model gauge group. These new
interactions lead to additional production processes for the exotic particles
in such mode... | physics |
7,423 | Chiral perturbation theory for hadrons containing a heavy quark: the sequel | hep-ph | Charm and bottom mesons and baryons are incorporated into a low energy chiral
Lagrangian. Interactions of the heavy hadrons with light octet Goldstone bosons
are studied in a framework which represents a synthesis of chiral perturbation
theory and the heavy quark effective theory. The differential decay rate for
the se... | physics |
7,424 | Rotation Curves of Spiral Galaxies and Large Scale Structure of Universe under Generalized Einstein Action | hep-ph | We consider an addition of the term which is a square of the scalar curvature
to the Einstein-Hilbert action. Under this generalized action, we attempt to
explain i) the flat rotation curves observed in spiral galaxies, which is
usually attributed to the existence of dark matter, and ii) the contradicting
observations ... | physics |
7,425 | Electroweak Breaking in Supersymmetric Models | hep-ph | We discuss the mechanism for electroweak symmetry breaking in supersymmetric
versions of the standard model. After briefly reviewing the possible sources of
supersymmetry breaking, we show how the required pattern of symmetry breaking
can automatically result from the structure of quantum corrections in the
theory. We ... | physics |
7,426 | Intermediate and Heavy Higgs Boson Physics at a 0.5 TeV e^+ e^- Collider | hep-ph | We explore the potential of a future e^+ e^- collider in the 0.5 TeV
center-of-mass energy range to detect intermediate or heavy Higgs bosons in the
Standard Model. We first briefly assess the production cross sections and
update the decay branching fractions for a Higgs boson of intermediate mass,
with M_Z < m_H < 2M_... | physics |
7,427 | Probing the $WWγ$ Vertex in $e^\pm p\toν\gammaX$ | hep-ph | We study the prospects of testing the $WW\gamma$ vertex in $e^- p\to\nu\gamma
X$ and $e^+ p\to\nu\gamma X$ at HERA and LEP/LHC. Destructive interference
effects between the Standard Model and the anomalous contributions to the
amplitude severely limit the sensitivity of both processes to non-standard
$WW\gamma$ couplin... | physics |
7,428 | A Tumbling Top-Quark Condensate Model | hep-ph | We propose a renormalizable model with no fundamental scalars which breaks
itself in the manner of a "tumbling" gauge theory down to the standard model
with a top-quark condensate. Because of anomaly cancellation requirements, this
model contains two color sextet fermions (quixes), which are vector-like with
respect to... | physics |
7,429 | Supersymmetry Protects the Primordial Baryon Asymmetry | hep-ph | It has been argued that any primordial B+L asymmetry existing at very high
temperatures can be subsequently erased by anomalous electroweak effects. We
argue that this is not necessarily the case in the supersymmetric standard
model because, apart from B and/or L, there are, above a certain temperature
$T_{SS}$, two ot... | physics |
7,430 | Heavy Mesons in Two Dimensions | hep-ph | The large mass limit of QCD uncovers symmetries that are not present in the
QCD lagrangian. These symmetries have been applied to physical (finite mass)
systems, such as B and D mesons.
We explore the validity of this approximation in the 't Hooft model
(two-dimensional QCD in the large-N approximation). We find that... | physics |
7,431 | Chiral Perturbation Theory for $f_{D_S}/f_D$ and $B_{B_S}/B_{B}$ | hep-ph | The decay constants for the $D$ and $D_S$ mesons, denoted $f_D$ and $f_{D_S}$
respectively, are equal in the $SU(3)_V$ limit, as are the hadronic amplitudes
for $B_S-\bar B_S$ and $B^0-\bar B^0$ mixing. The leading $SU(3)_V$ violating
contribution to $\left( f_{D_S} / f_D \right)$ and to the ratio of hadronic
matrix el... | physics |
7,432 | An Introduction to Spin Dependent Deep Inelastic Scattering | hep-ph | The main focus of these lectures is on those aspects of deep inelastic
scattering that can be derived directly from QCD using quantum field theory,
without recourse to phenomenological models. The emphasis is on spin dependent
scattering, but the theory of spin averaged scattering is also discussed. A
detailed analysis... | physics |
7,433 | 4-dimensional spontaneously broken U(1)L gauge theories with a composite Wess-Zumino field | hep-ph | Some spontaneously broken gauge theories with left couplings to fermions,
like the abelian model that we propose here, can be endowed with a composite
scalar sector and Wess-Zumino field ; their quantization in the functionnal
integral formalism accordingly requires the introduction of constraints that,
together with t... | physics |
7,434 | Comment on ``High Temperature Fermion Propagator -- Resummation and Gauge Dependence of the Damping Rate'' | hep-ph | Baier et al. have reported the damping rate of long-wavelength fermionic
excitations in high-temperature QED and QCD to be gauge-fixing-dependent even
within the resummation scheme due to Braaten and Pisarski. It is shown that
this problem is caused by the singular nature of the on-shell expansion of the
fermion self-e... | physics |
7,435 | Effective Field Theory of Anomalous Gauge-Boson Couplings at High-Energy pp Colliders | hep-ph | We compute the effects of anomalous gauge-boson couplings at high-energy
hadron colliders using next-to-leading order $SU(2) \times SU(2)$ chiral
perturbation theory. By comparing the yields from the universal $p^2$ terms
with those arising from new physics at order $p^4$, we estimate the sensitivity
of the SSC and LHC... | physics |
7,436 | Quark solitons as constituents of hadrons | hep-ph | We exhibit static solutions of multi-flavour QCD in two dimensions that have
the quantum numbers of baryons and mesons, constructed out of quark and
anti-quark solitons. In isolation the latter solitons have infinite energy,
corresponding to the presence of a string carrying the non-singlet colour flux
off to spatial i... | physics |
7,437 | Scalar--Tensor Theories of Gravity with \PHI Dependent Masses | hep-ph | We study new physical phenomena and constraints in generalized scalar--tensor
theories of gravity with $\Phi$--dependent masses. We investigate a scenario
(which can arise in string theories) with two types of $\Phi$--dependent masses
which could correspond to visible and dark matter sectors. The parameters of
this the... | physics |
7,438 | Non-Oblique Effects in the Z b b_bar Vertex from ETC Dynamics | hep-ph | Extended technicolor theories generate potentially large corrections to the
$\Zbb$ vertex which can be observed in current experiments at LEP. | physics |
7,439 | A new ansatz for quark and lepton mass matrices | hep-ph | A new ansatz for quark and lepton mass matrices is proposed in the context of
supersymmetric grand unified theories. The 13 parameters describing fermion
masses and mixings are determined in terms of only 6 free parameters, allowing
7 testable predictions. The values of $V_{us}$, $V_{cb}$, $V_{ub}$, $m_u$,
$m_d$, $m_s$... | physics |
7,440 | Resummation in a Hot Scalar Field Theory | hep-ph | A resummed perturbative expansion is used to obtain the self-energy in the
high-temperature \(g^2\phi^4\) field theory model up to order $g^4$. From this
the zero momentum pole of the effective propagator is evaluated to determine
the induced thermal mass and damping rate for the bosons in the plasma to order
$g^3$. Th... | physics |
7,441 | Two--Body Decays of $B_s$ Mesons | hep-ph | We have calculated the decay rates of the $B_s$ meson in a number of
exclusive two--body decay channels using the Bauer--Stech--Wirbel model for
current matrix elements. The influence of the free parameters of the model on
the predictions is studied. The total branching ratio of the $B_s$ into final
states which only c... | physics |
7,442 | On the Renormalization of the S Parameter | hep-ph | We calculate the S parameter of the standard model at one loop of fermions,
using three different regularizations (dimensional, Pauli-Villars and lattice)
and find an extra contribution to the S parameter besides the standard one for
each case. This shows that the extra contribution recently reported for the
lattice re... | physics |
7,443 | A QCD Calculation of the Interaction of Quarkonium with Nuclei | hep-ph | The interaction of quarkonium with nuclei is studied in the $m_Q\rightarrow
\infty$ limit of QCD, where the binding energy is found to be exactly
computable. The dominant contribution to the interaction is from two-gluon
operators. The forward matrix elements of these two-gluon operators can be
determined from the QCD ... | physics |
7,444 | Colored Pseudo-Goldstone Bosons and Gauge Boson Pairs | hep-ph | If the electroweak symmetry breaking sector contains colored particles
weighing a few hundred GeV, then they will be copiously produced at a hadron
supercollider. Colored technipions can rescatter into pairs of gauge bosons. As
proposed by Bagger, Dawson, and Valencia, this leads to gauge boson pair rates
far larger th... | physics |
7,445 | QCD renormalization for the top-quark mass in a mass geometrical mean hierarchy | hep-ph | $QCD$ renormalization for the top-quark mass is calculated in a mass
geometrical mean hierarchy, $m_d m_b = m_s^2$ and $m_u m_t = m_c^2$. The
physical mass, $m_t(m_t) = 160 {\pm} 50 GeV$ is obtained, which agrees very
well with electroweak precision measurement. | physics |
7,446 | Unusual high-pT jet events at HERA | hep-ph | We calculate the cross-section for events at HERA where the proton loses only
a minute fraction of its initial energy, all of which goes into producing a
single pair of transverse jets. | physics |
7,447 | On tunneling at finite energies and temperatures | hep-ph | We study the contribution of finite energy tunneling to the total vacuum
transition rate in a system at finite temperature. We find that in certain
models, such as the 1+1 Abelian Higgs model, the quantum contribution is
non-negligible even at large temperatures. We show how the persistence of the
cosmological baryon a... | physics |
7,448 | Proton $β% decay in large magnetic fields | hep-ph | A delicate interplay between the anomalous magnetic moments of the proton and
neutron makes, in magnetic fields $B\ge 2\times 10^{14}$ T, the neutron stable
and for fields $B\ge 5\times 10^{14}$ T the proton becomes unstable to a decay
into a neutron via $\beta$ emission. Limits on the field strengths for which
these a... | physics |
7,449 | Mass and mixing angle patterns in the Standard Model and its Minimal Supersymmetric Extension | hep-ph | Using renormalization group techniques, we examine several interesting
relations among masses and mixing angles of quarks and leptons in the Standard
Model. We extend the analysis to the minimal supersymmetric extension to
determine its effect on these mass relations. Remarkably Supersymmetry allows
for these relations... | physics |
7,450 | Signals for Virtual Leptoquark Exchange at HERA | hep-ph | We study the effects of virtual leptoquarks on charged current and neutral
current processes at the $ep$ collider HERA. We present the areas of parameter
space that can be excluded at HERA by searching for deviations from Standard
Model expectations. The best results are obtained by examining the ratio of
neutral curre... | physics |
7,451 | Superconductivity Solves the Monopole Problem for Alice Strings | hep-ph | Alice strings are cosmic strings that turn matter into antimatter. Although
they arise naturally in many GUT's, it has long been believed that because of
the monopole problem they can have no cosmological effects. We show this
conclusion to be false; by using the Langacker-Pi mechanism, monopoles can in
fact be annihil... | physics |
7,452 | Phase Transition Temperatures at Next-to-Leading Order | hep-ph | Broken gauge symmetries are typically restored at high temperature, and the
leading-order result for the critical temperature $T_c$ was found many years
ago by Weinberg and by Dolan and Jackiw. I find a simple expression for the
next-to-leading order correction to $T_c$, which is order $e T_c$ where $e$ is
the gauge co... | physics |
7,453 | The Residual Mass Term in the Heavy Quark Effective Theory | hep-ph | We reformulate the heavy quark effective theory in the presence of a residual
mass term, which has been taken to vanish in previous analyses. While such a
convention is permitted, the inclusion of a residual mass allows us to resolve
a potential ambiguity in the choice of the expansion parameter which defines
the effec... | physics |
7,454 | Confinement in a Chromoelectric Vacuum | hep-ph | A chromoelectric vacuum that confines both gluon and quark degrees of freedom
(in the sense that they do not exist as asymptotic states) is constructed.
However some degrees of freedom still exist as asymptotic states thereby
allowing colour singlets to propagate. | physics |
7,455 | Reaction rate in a heat bath | hep-ph | We show in detail how the presence of a heat bath of photons effectively
gives charged particles in the final state of a decay process a
temperature-dependent mass, and changes the effective strength of the force
responsible for the decay. At low temperature, gauge invariance causes both
these effects to be largely can... | physics |
7,456 | New Tools for Analyzing Quark Mixing | hep-ph | We present some new mathematical tools which help to derive information about
the quark mass matrices directly from experimental data and to elucidate the
structure of these mass matrices. | physics |
7,457 | CP-violating Phenomena in an $ SU(2)_L \times SU(2)_R \times U(1)_{B-L} \times SU(3)_H^{VL}$ Horizontal Symmetric Model | hep-ph | We consider an $SU(2)_L \times SU(2)_R \times U(1)_{B-L} \times SU(3)_H^{VL}$
gauge model with natural flavour conservation in the Higgs sector, in which
CP-violation occurs due to the horizontal interactions only. We calculate the
CP-violating observables $\epsilon$ and $\epsilon'$ of the neutral kaon sector
and $d_n$... | physics |
7,458 | Threshold Effects in SO(10) Grandunified Models and Solar Neutrino Puzzle | hep-ph | We compute the threshold uncertainties due to unknown masses of the Higgs
bosons on the predictions for the intermediate and unification scales, $M_I$
and $M_U$ respectively in SO(10) models.We focus on models with separate
breaking scales for Parity and $SU(2)_R$ symmetries since they provide a
natural realization of ... | physics |
7,459 | Ginzburg-Landau Theory of the Electroweak Phase Transition and Analytical Results | hep-ph | The phase transition of the electroweak vacuum induced by a strong magnetic
field is examined, and a connection is made with the Ginzburg-Landau theory of
type-II superconductivity. For solutions of the exact nonlinear field equations
of the electroweak theory with lattice periodicity in directions perpendicular
to the... | physics |
7,460 | The Propagation of Quarks in the Spatial Direction in Hot QCD | hep-ph | The dynamics of {\it light} fermions propagating in a spatial direction at
high temperatures can be described effectively by a two--dimensional
Schr\"odinger equation with {\it heavy} effective mass $m_{\rm eff} = \pi T$.
Starting from QED, we discuss the transition from three-- to two--dimensional
positronium discussi... | physics |
7,461 | Heavy Hadron Form Factor Relations for $m_c\ne\infty$ and $\bas(m_c)\ne0$ | hep-ph | First order power corrections to current matrix elements between heavy meson
or $\Lambda_\Q$ baryon states are shown to vanish at the zero recoil point to
all orders in QCD. Five relations among the six form factors that parametrize
the semileptonic decay $\Lambda_b \to \Lambda_c e \overline{\nu}$ are also
demonstrated... | physics |
7,462 | Semileptonic $B_c$ Decay and Heavy Quark Spin Symmetry | hep-ph | Semileptonic decay of the $B_c$ meson is studied in the heavy quark limit.
The six possible form factors for $B_c \rightarrow B_s (B^0),B_s^* (B^{*0})$
semileptonic decay are determined by two invariant functions. Only one of these
functions contributes at zero recoil, where it is calculable to lowest order in
an opera... | physics |
7,463 | Virtual bremsstrahlung from pions and quarks in thermalized hadronic matter | hep-ph | A soft photon approximation is used to calculate the rates of lepton pair
production through virtual bremsstrahlung from both pions and quarks. Standard
assumptions about the evolution of a nuclear system under collision allow pion
and quark driven total production to be calculated. Comparisons are made with
Dalitz dec... | physics |
7,464 | Production of the Lightest Supersymmetric Particle in Electron-Photon Collisions | hep-ph | We present cross sections for the production of the lightest supersymmetric
particle as a neutralino state in the minimal supersymmetric standard model at
electron-photon colliders. The lightest supersymmetric particle mass is taken
at a value of 30 GeV which is slightly higher than its lowest experimental
bound of 20 ... | physics |
7,465 | Is CP a Gauge Symmetry? | hep-ph | We suggest here that CP is a discrete {\it gauge} symmetry, and is therefore
not violated by quantum gravity. We show that four dimensional CP can arise as
a discrete gauge symmetry in theories with dimensional compactification, if the
original number of Minkowski dimensions equals $8k+1$, $8k+2$ or $8k+3$, and if
ther... | physics |
7,466 | A Realistic Technicolor Model from 150 TeV down | hep-ph | A realistic technicolor model is presented with the dynamics below $150$ TeV
treated explicitly. Electroweak symmetry is broken by the condensates of a
`minimal' doublet of technifermions. The new feature of the model is that the
the third generation quarks are unified with the technifermions into multiplets
of a walki... | physics |
7,467 | Vacuum Alignment in "Composite Technicolor" Models | hep-ph | We consider the question of vacuum alignment in the recently proposed
"composite technicolor" (CTC) models. In order for these models to work, an
"ultrafermion" condensate must align in a particular way, driven by the
competition between ultrafermion masses and "flavor" gauge boson exchange. We
show that for ultrafermi... | physics |
7,468 | Field Theory Without Feynman Diagrams: One-Loop Effective Actions | hep-ph | In this paper the connection between standard perturbation theory techniques
and the new Bern-Kosower calculational rules for gauge theory is clarified. For
one-loop effective actions of scalars, Dirac spinors, and vector bosons in a
background gauge field, Bern-Kosower-type rules are derived without the use of
either ... | physics |
7,469 | R parity can spontaneously break | hep-ph | We refute the claims made by Chaichian and Smilga in a recent paper in Phys
Rev Letters on the impossibility of spontaneous R Parity breaking. Apart from
explaining their error we summarize the results of a more detailed work that
demonstrates explicitly that R parity can break spontaneously at a scale
anywhere in the ... | physics |
7,470 | Contributions to the W-Boson Anomalous Moments in the Two-Higgs-Doublet Model at Collider Energies | hep-ph | We examine the one loop contributions arising in the Two-Higgs-Doublet Model
(THDM) to the W-boson anomalous magnetic dipole and electric quadrupole form
factors for both photon and Z couplings relevant at collider energies. While
the model parameter and $q^2$-dependencies of these form factors are found to
be signific... | physics |
7,471 | Supersymmetric Signals in Electron-Photon Collision | hep-ph | Associated selectron-neutralino production in the process $e^-\gamma\to\tilde
e^-\tilde\chi^0$ provides a striking supersymmetric signal: events with a
single high $p_\perp$ electron and otherwise only invisible particles. For
$e^-\gamma$ collisions obtained at high energy linear colliders through
back-scattering of a ... | physics |
7,472 | The Chiral Anomaly in Non-Leptonic Weak Interactions | hep-ph | The interplay between the chiral anomaly and the non-leptonic weak
Hamiltonian is studied. The structure of the corresponding effective Lagrangian
of odd intrinsic parity is established. It is shown that the factorizable
contributions (leading in $1/N_C$) to that Lagrangian can be calculated without
free parameters. As... | physics |
7,473 | Quark-Antiquark Regge Trajectories in Large N_c QCD | hep-ph | We apply methods developed by Lovelace, Lipatov and Kirschner to evaluate the
leading Regge trajectories \alpha(t) with the quantum numbers of nonexotic
quark-antiquark mesons at N_c = infinity and in the limit of t going to minus
infinity. In this region renormalization group improved perturbation theory
should be val... | physics |
7,474 | Grand Unification, Gravitational Waves, and the Cosmic Microwave Background Anisotropy | hep-ph | We re-examine the gravitational wave background resulting from inflation and
its effect on the cosmic microwave background radiation. The new COBE
measurement of a cosmic background quadrupole anisotropy places an upper limit
on the vacuum energy during inflation of $\approx 5 \times 10^{16}$ GeV. A
stochastic backgrou... | physics |
7,475 | Large-order perturbation theory for the electromagnetic current-current correlation function | hep-ph | The constraints imposed by asymptotic freedom and analyticity on the
large-order behavior of perturbation theory for the electromagnetic
current-current correlation function are examined. By suitably applying the
renormalization group, the coefficients of the asymptotic expansion in the deep
Euclidean region may be exp... | physics |
7,476 | Oscillations of Pseudo-Dirac Neutrinos and the Solar Neutrino Problem | hep-ph | The oscillations of pseudo-Dirac neutrinos in matter are discussed and
applied to the solar neutrino problem. Several scenarios such as both $\nu_e$
and $\nu_{\mu}$ being pseudo-Dirac and only $\nu_e$ or $\nu_{\mu}$ being
pseudo-Dirac are examined. It is shown that the allowed region in the
mass-mixing angle parameter ... | physics |
7,477 | Dark Matter with Variable Masses | hep-ph | String effective theories contain a dilaton scalar field which couples to
gravity, matter and radiation. In general, particle masses will have different
dilaton couplings. We can always choose a conformal frame in which baryons have
constant masses while (non--baryonic) dark matter have variable masses, in the
context ... | physics |
7,478 | Screening of Very Intense Magnetic Fields by Chiral Symmetry Breaking | hep-ph | In very intense magnetic fields, $B > 1.5\times 10^{14}$ T, the breaking of
the strong interaction $SU(2)\times SU(2)$ symmetry arranges itself so that
instead of the neutral $\sigma$ field acquiring a vacuum expectation value it
is the charged $\pi$ field that does and the magnetic field is screened.
Details are prese... | physics |
7,479 | New Probes for Extended Gauge Structures at HERA | hep-ph | Doncheski and Hewett have recently shown that the ratio of neutral current to
charged current cross sections, $R={\sigma_{NC}}/{\sigma_{CC}}$, can provide a
more sensitive probe for the existence of heavy leptoquarks at HERA than the
usual proceedure which makes use of neutral current asymmetries. The apparent
reason f... | physics |
7,480 | A General Lower Bound for Radiative B Decay | hep-ph | In a wide class of models -- including the standard model -- flavor-changing
neutral currents are suppressed by an approximate chiral symmetry of the
low-energy lagrangian. This symmetry allows the derivation of general relations
among low-energy flavour-changing processes. We derive one such: the relative
sizes of the... | physics |
7,481 | Fast Neutrino Decay in the Minimal Seesaw Model | hep-ph | Neutrino decay in the minimal seesaw model containing three right handed
neutrinos and a complex $SU(2)\times U(1)$ singlet Higgs in addition to the
standard model fields is considered. A global horizontal symmetry $U(1)_H$ is
imposed, which on spontaneous breaking gives rise to a Goldstone boson. This
symmetry is chos... | physics |
7,482 | Nonfactorizable Amplitudes in Weak Nonleptonic Decays of Heavy Mesons | hep-ph | We discuss nonfactorizable $1/N_c$ contributions in the amplitudes of
non-leptonic exclusive decays of the type $B\rightarrow D\pi$ ($N_c$ is the
number of colors). In a certain kinematical limit rather reliable estimates are
possible. It is demonstrated that the nonfactorizable parts are of the same
order as the facto... | physics |
7,483 | Constraints on Mirror Fermion Mixing Angles from Anomalous Magnetic Moment Data | hep-ph | The new contributions to the electron (muon) anomalous magnetic moment
arising in mirror fermion theories have been calculated. Imposing the
experimental constraint lowers the current upper bound on the ordinary - mirror
lepton mixing angles by a factor of 50 making predictions for mirror lepton
production at HERA unde... | physics |
7,484 | $θ$ Bag and Quark Confinement | hep-ph | We propose $\theta$ bag through the wall separating $\theta=0$ and
$\theta=\pi$. $\theta$ may or may not be a dynamical field generating the wall.
For a massive pseudo scalar $\theta$, we present a two Higgs doublet model. We
also presnt an idea for quark confinement within this $\theta$ bag scheme. | physics |
7,485 | Axions with Variable Masses | hep-ph | Axions with variable masses, in the context of a scalar--tensor gravity
theory, give a large entropy production during the matter era. The subsequent
axion dilution is proportional to their present energy density. Depending on
the parameters ($\beta_I,\beta_V$) of the model, this dilution relaxes or even
eludes the cos... | physics |
7,486 | Strong CP-Problem in Superstring Theory | hep-ph | We apply the solution for the strong CP-problem in the 4-dimensional
superstring theory recently proposed by Ib${\rm\acute{a}\tilde{n}}$ez and
L${\rm\ddot{u}}$st to Calabi-Yau type models and study its phenomenological
aspects. In Calabi-Yau type models there seem to be phenomenologically
difficult problems in the axio... | physics |
7,487 | Recent Developments in Superstring Phenomenology | hep-ph | Recent developments in superstring phenomenology are summarized on a
non-technical level. (Talk presented at the XXVIIth Rencontre de Moriond on
Electroweak Interactions and Unified Theories.) | physics |
7,488 | Supersymmetry, Naturalness, and Dynamical Supersymmetry Breaking | hep-ph | Models with dynamical supersymmetry breaking have the potential to solve many
of the naturalness problems of hidden sector supergravity models. We review the
argument that in a generic supergravity theory in which supersymmetry is {\it
dynamically} broken in the hidden sector, only tiny Majorana masses for
gauginos are... | physics |
7,489 | Reparameterisation Invariance Constraints on Heavy Particle Effective Field Theories | hep-ph | Since fields in the heavy quark effective theory are described by both a
velocity and a residual momentum, there is redundancy in the theory: small
shifts in velocity may be absorbed into a redefinition of the residual
momentum. We demonstrate that this trivial reparameterisation invariance has
non-trivial consequences... | physics |
7,490 | Axino Mass | hep-ph | The mass of the axino is computed in realistic supersymmetric extensions of
the standard model. It is found to be strongly model dependent and can be as
small as a few keV but also as large as the gravitino mass. Estimates of this
mass can only be believed once a careful analysis of the scalar potential has
been perfor... | physics |
7,491 | Planck-Scale Physics and Neutrino Masses | hep-ph | We discuss gravitationally induced masses and mass splittings of Majorana,
Zeldovich-Konopinski-Mahmoud and Dirac neutrinos. Among other implications,
these effects can provide a solution of the solar neutrino puzzle. In
particular, we show how this may work in the 17 keV neutrino picture. | physics |
7,492 | Z(N) interface tension in a hot SU(N) gauge theory | hep-ph | The interface tension between Z(N) vacua in a hot SU(N) gauge theory (without
dynamical fermions) is computed at next to leading order in weak coupling. The
Z(N) interface tension is related to the instanton of an effective action,
which includes both classical and quantum terms; a general technique for
treating consis... | physics |
7,493 | Finite Temperature Scalar Potential from a 1/N Expansion | hep-ph | We compute the leading and next--to--leading corrections to the finite
temperature scalar potential for a 3+1 dimensional $\phi^4$ theory using a
systematic $1/N$ expansion. Our approach automatically avoids problems
associated with infrared divergences in ordinary perturbation theory in
$\hbar$. The leading order resu... | physics |
7,494 | Bounds on Microscopic Physics from P and T Violation in Atoms and Molecules | hep-ph | Atomic and molecular electric dipole moments are calculated within the
minimal supersymmetric standard model. Present experiments already provide
strong bounds on the combination of phases responsible for the dipole moments
of the neutron and closed shell atoms. For a supersymmetry breaking scale of
100 GeV, these phas... | physics |
7,495 | Computing the Weak Mixing Angle from Anomaly Cancellation | hep-ph | I remark that the weak mixing angle in the standard model may be computed
even in the absence of a grand unification symmetry. In particular, if there is
an additional gauged $U(1)$ symmetry at some large scale which can be made
anomaly-free only by a Green-Schwarz (GS) mechanism, this typically results in
a prediction... | physics |
7,496 | Covariant gauges at finite temperature | hep-ph | A prescription is presented for real-time finite-temperature perturbation
theory in covariant gauges, in which only the two physical degrees of freedom
of the gauge-field propagator acquire thermal parts. The propagators for the
unphysical degrees of freedom of the gauge field, and for the Faddeev-Popov
ghost field, ar... | physics |
7,497 | Dispersion Relations in Quantum Chromodynamics | hep-ph | Dispersion relations for the scattering of hadrons are considered within the
framework of Quantum Chromodynamics. It is argued that the original methods of
proof remain applicable. The setting and the spectral conditions are provided
by an appropriate use of the BRST cohomology. Confinement arguments are used in
order ... | physics |
7,498 | Best Fit to the Gluino Mass | hep-ph | Assuming that perturbative QCD is the dominant explanation for the narrowness
of the vector quarkonia, we perform a $\chi^2$ minimization analysis of their
hadronic decays as a function of two parameters, the mass of the gluino and the
value of ${\alpha}_3(M_Z)$. A value below 1 GeV for the gluino mass is strongly
pref... | physics |
7,499 | Radiative Correction Effects of a Very Heavy Top | hep-ph | If the top is very heavy, m_t >> M_Z, the dominant radiative correction
effects in all electroweak precision tests can be exactly characterized in
terms of two quantities, the rho-parameter and the GIM violating Z -> b bbar
coupling. These quantities can be computed using the Standard Model Lagrangian
with vanishing ga... | physics |
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