publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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1997-01-23 | Z' effects and anomalous gauge couplings at LC with polarization | We show that the availability of longitudinally polarized electron beams at a
500 GeV Linear Collider would allow, from an analysis of the reaction e^+e^-\to
W^+W^-, to set stringent bounds on the couplings of a Z' of the most general
type. In addition, to some extent, it would be possible to disentangle
observable eff... | 9701359v2 |
1997-02-12 | The Running Gauge Coupling in the Exact Renormalization Group Approach | We discuss the perturbative running Yang-Mills coupling constant in the
Wilsonian exact renormalization group approach, and compare it to the running
coupling in the more conventional MS-bar scheme. The exact renormalization
group approach corresponds to a particular renormalization scheme, and we
relate explicitly the... | 9702309v1 |
1997-03-28 | Direct Top Quark Production at Hadron Colliders as a Probe of New Physics | We examine the effect of an anomalous flavor changing chromomagnetic moment
which allows direct top quark production (two partons combining into an
unaccompanied single top quark in the s-channel) at hadron colliders. We
consider both t-c-g and t-u-g couplings. We find that the anomalous charm quark
coupling parameter ... | 9703450v1 |
1997-04-08 | Probing Anomalous Wtb Coupling via Single Top Production at TeV Energy $γ$ e Colliders | Results of complete tree level calculations of the single top production
reaction $\gamma e \to \nu \bar{t} b$ at the Next Linear Collider, including
the contribution of anomalous operators to the Wtb coupling are presented. The
sensitivity for probing the structure of the Wtb coupling in a model
independent way is ana... | 9704259v1 |
1997-04-16 | Searching For Anomalous $τνW$ Couplings | The capability of current and future measurements at low and high energy
$e^+e^-$ colliders to probe for the existence of anomalous, CP conserving,
$\tau \nu W$ dipole moment-type couplings is examined. At present, constraints
on the universality of the tau charged and neutral current interactions as well
as the shape ... | 9704337v1 |
1997-05-12 | Power corrections and Landau singularity | In the dispersive approach of Dokshitzer, Marchesini and Webber, standard
power-behaved contributions of infrared origin are described with the notion of
an infrared regular QCD coupling. I argue that their framework suggests the
existence of non-standard contributions, arising from short distances (hence
unrelated to ... | 9705290v1 |
1997-06-10 | Evolution of the gluon density in x with a running coupling constant | This is a draft describing the calculation of the evolution of the gluon
density in $x$ from an initial value $x=x_{0}=0.01$ to smaller values, up to
$x=10^{-8}$ in the hard pomeron formalism with a running coupling introduced on
the basis of the bootstrap equation. The obtained gluon density is used to
calculate the s... | 9706314v1 |
1997-06-16 | Hadronic Couplings Via QCD Sum Rules Using Three-Point Functions: Vacuum Susceptibilities | We develop a three-point formalism to treat vacuum susceptibilities used for
the coupling of currents to hadrons within the method of QCD Sum Rules. By
introducing nonlocal condensates, with the space-time structure taken from fits
to experimental parton distrbutions, we show that one can treat hadronic
coupling at zer... | 9706376v1 |
1997-07-10 | Non-Leptonic Decays of B Mesons and Strong Coupling Constants | Non-leptonic decays of B mesons into two mesons or meson resonances are
studied on the basis of two versions of simple pole-dominance models involving
scalar, vector, pseudoscalar and axial-vector poles. The results are compared
with those obtained from the usual factorization model and used to obtain
information on st... | 9707304v2 |
1997-07-28 | Recent Progress in Weakly-Coupled Heterotic String Phenomenology | Some recent developments in the weakly-coupled heterotic string phenomenology
are reviewed. We discuss several important issues such as dilaton/moduli
stabilization, supersymmetry breaking (by hidden-sector gaugino condensation),
gauge coupling unification (or the Newton's constant), the QCD axion, as well
as cosmologi... | 9707498v1 |
1997-09-01 | Semi-analytic predictions for W pair production at 500 GeV | We give a short review on the semi-analytic approach to off-shell W pair
production at 500 GeV and above. Numerical calculations are performed with the
Fortran program GENTLE v. 2.0 and its upgrade. Recent extensions include: (i)
angular distribution for the CC11 process with LLA QED corrections; (ii)
anomalous couplin... | 9709207v1 |
1997-10-02 | CP-odd Anomalous W-boson Couplings from Supersymmety | The supersymmetric standard model contains a new CP-violating phase in the
mass matrices for charginos and neutralinos, which could induce CP-odd
anomalous couplings for the WWZ and WW\gamma vertices at the one-loop level. We
study these couplings, paying attention to the model-parameter and q^2
dependencies. It is sho... | 9710220v1 |
1997-10-09 | Minimal SU(5) Resuscitated by Higgs Coupling Fixed Points | The issue of gauge unification in the (non-supersymmetric) Standard Model is
reinvestigated. It is found that with just an additional fourth generation of
quarks and leptons, $SU(3) \otimes SU(2) \otimes U(1)$ gauge couplings converge
to a common point $\sim 2.65 \times 10^{15}$ GeV ($\tau_p \sim 10^{34 \pm 1}$
years) ... | 9710297v2 |
1997-10-20 | QCD Corrections and Anomalous Couplings in $Zγ$ Production at Hadron Colliders | The processes $pp/ pbar p \to Z \gamma + X \to \ell^+ \ell^- \gamma + X$
($\ell=e, \mu$) and $pp/ pbarp \to Z \gamma + X \to \bar\nu\nu\gamma + X$ are
calculated to ${\cal O}(\alpha_s)$ for general $ZZ\gamma$ and $Z\gamma\gamma$
couplings. The impact of ${\cal O}(\alpha_s)$ QCD corrections on the
observability of $ZZ\g... | 9710416v1 |
1997-11-24 | Four-Fermion Production with Anomalous Couplings at LEP2 and NLC | I give a short report on the semi-analytical approach to off-shell W pair
production. In particular, I show the effects of irreducible background
diagrams of the CC11 class in the differential cross-section. Further, I study
the influence of potential anomalous couplings at a future linear collider and
investigate the ... | 9711439v1 |
1997-11-24 | Search for Non-standard Higgs Boson in Diphoton Events at p pbar Collisions | We estimate the attainable limits on the coupling of a non-standard Higgs
boson to two photons taking into account the data collected by the Fermilab
collaborations on diphoton events. We based our analysis on a general set of
dimension--6 effective operators that give rise to anomalous couplings in the
bosonic sector ... | 9711446v1 |
1997-11-28 | Quark flavour conserving violations of the lepton number | We study supersymmetric models of lepton and baryon number violation based on
an abelian family gauge group. Due to possible lepton-Higgs mixing, the lepton
violating couplings are related to the Yukawa couplings and may be generated by
them even if they were absent in the original theory. Such terms may be
dominant an... | 9711517v1 |
1997-12-19 | Measuring Trilinear Gauge Boson Couplings at Hadron and Lepton Colliders | We discuss the measurement of the $WWV$ ($V=\gamma,\, Z$) gauge boson
couplings in present and future collider experiments. The major goals of such
experiments will be the confirmation of the Standard Model (SM) predictions and
the search for signals of new physics. The present limits on these couplings
from Tevatron a... | 9712433v1 |
1998-01-26 | Comment on "Suppression of piNN* Coupling and Chiral Symmetry" | Jido, Oka and Hosaka have shown that the p-slash gamma_5 piece of the
pion-to-vacuum correlator of two baryon interpolating fields vanishes in the
soft-pion limit, as a consequence of chiral transformation properties of those
fields. This is a statement about the particular combination of pion-baryon
couplings and subt... | 9801413v2 |
1998-02-14 | Constraints on R parity and B violating couplings in gauge-mediated supersymmetry breaking models | We consider the proton decay involving a light gravitino or axino in
gauge-mediated supersymmetry breaking models to derive constraints on the $R$
parity and baryon number violating Yukawa couplings. Bounds on all nine
coupling constants are obtained by considering the decay amplitudes at one-loop
order. | 9802323v1 |
1998-02-28 | Confinement from a massive scalar in QCD | A model is introduced with a massive scalar coupling to the Yang--Mills term
in four--dimensional gauge theory. It is shown that the resulting potential of
colour sources consists of a short range Coulomb interaction and a long range
confining part. Far away from the source the scalar vanishes $\sim r^{-1}$
while the p... | 9803209v1 |
1998-04-19 | On the enhancement of the QCD running coupling | We show that the existence of the fundamental ultraviolet cut-off (minimal
scale) fixed by weak interactions enhances the QCD running coupling evaluated
at one quantum loop level, starting at the scale in the vicinity of the
cut-off. The enhancement of the QCD running coupling could completely explain
the observed anom... | 9804326v2 |
1998-04-22 | Perturbative reliability of the Higgs-boson coupling in the standard electroweak model | We apply Pade summation to the \beta(\lambda) function for the quartic Higgs
coupling \lambda in the standard electroweak model. We use the \beta function
calculated to five loops in the minimal subtraction scheme to demonstrate the
improvement resulting from the summation, and then apply the method to the more
physica... | 9804362v1 |
1998-05-01 | Running Coupling Effects in BFKL Evolution | We resum the recently calculated second order kernel of the BFKL equation.
That kernel can be viewed as the sum of a conformally invariant part and a
running coupling part. The conformally invariant part leads to a corrected BFKL
intercept as found earlier. The running coupling part of the kernel leads to a
non-Regge t... | 9805208v2 |
1998-05-06 | Supergravity Resolution of the Unification to Planck Scale Hierarchy | It is demonstrated how the hierarchy between the gauge coupling unification
scale of minimal supersymmetry and the Planck (or string) scale, which
resembles in order of magnitude a loop factor, can actually be explained as
such in supergravity-coupled supersymmetry. A gauge and global singlet field
acquires a linear po... | 9805240v1 |
1998-05-13 | Probing Top-Quark Couplings at Polarized NLC | The energy spectrum of the lepton(s) in e^+e^- --> tt-bar --> l^{+-}
...../l^+l^-..... at next linear colliders (NLC) is studied for arbitrary
longitudinal beam polarizations as a possible test of new physics in top-quark
couplings. The most general non-standard couplings for gamma-tt-bar, Ztt-bar
and Wtb vertices are ... | 9805318v2 |
1998-05-14 | Phenomenology and cosmology of weakly coupled string theory | The weakly coupled vacuum of $E_8\otimes E_8$ heterotic string theory remains
an attractive scenario for phenomenolgy and cosmology. The particle spectrum is
reviewed and the issues of gauge coupling unification, dilaton stabilization
and modular cosmology are discussed. A specific model for condensation and
supersymme... | 9805320v2 |
1998-05-27 | QCD Power Corrections from a Simple Model for the Running Coupling | A simple parametrization of the QCD running coupling at low scales is
introduced and used to illustrate various schemes for the estimation of
non-perturbative power corrections. The `infrared matching' scheme proposed
earlier gives satisfactory results when combined with next-to-leading (or
higher) order perturbative p... | 9805484v1 |
1998-09-24 | Limits on a Light Leptophobic Gauge Boson | We consider the phenomenology of a naturally leptophobic $Z$-prime boson in
the 1 to 10 GeV mass range. The $Z$-prime's couplings to leptons arise only via
a radiatively-generated kinetic mixing with the $Z$ and photon, and hence are
suppressed. We map out the allowed regions of the mass-coupling plane and show
that su... | 9809522v1 |
1998-10-06 | The suppression of $πN N(1535)$ coupling in QCD | The light cone QCD sum rules are employed to calculate the $\pi N N(1535)$
coupling $g_{\pi N N^\ast}$. We study the two point correlation function of two
nucleon currents sandwiched between the vacuum and the pion state. The
contribution from the excited states and the continuum is subtracted cleanly
through double Bo... | 9810255v1 |
1998-11-18 | Anomalous Higgs Couplings at Colliders | I summarize our results on the attainable limits on the coefficients of
dimension-6 operators from the analysis of Higgs boson phenomenology using data
taken at Tevatron RUNI and LEPII. Our results show that the coefficients of
Higgs-vector boson couplings can be determined with unprecedented accuracy.
Assuming that th... | 9811389v1 |
1998-11-28 | R-parity-violating trilinear couplings and recent neutrino data | The nontrivial structure of the neutrino mass matrix, suggested by the recent
Super-Kamiokande results and data from other neutrino experiments, can be
reproduced in R-parity-violating supersymmetric theories. This requires sets of
products of R-parity-violating trilinear couplings to take appropriately chosen
values. ... | 9811500v2 |
1998-12-01 | The g_(Ko* K pi) coupling constant in QCD | The strong coupling constant g_(Ko* K pi) of the scalar Ko* meson decay to (K
pi) is calculated in light cone QCD sum rule. The predicted value of the
coupling constant g_(Ko* K pi) is in a good agreement with the experimental
result. | 9812213v1 |
1998-12-02 | Hybrid inflation with running inflaton mass | We realize and study a model of hybrid inflation in the context of softly
broken supersymmetry. The inflaton is taken to be a flat direction in the
superfield space and, due to unsuppressed couplings, its soft supersymmetry
breaking mass runs with scale. Both gauge and Yukawa couplings are taken into
account and differ... | 9812232v1 |
1998-12-18 | Anomalous Gauge Boson Couplings in the e^+ e^- -> ZZ Process | We discuss experimental aspects related to the $\mathrm{e^+ e^-} \to
\mathrm{Z}\mathrm{Z}$ process and to the search for anomalous ZZV couplings
(V$= \mathrm{Z}, \gamma$) at LEP2 and future $\mathrm{e^+ e^-}$ colliders. We
present two possible approaches for a realistic study of the reaction and
discuss the differences... | 9812435v3 |
1999-01-09 | Determination of the dynamically generated Yukawa coupling in supersymmetric QCD | The strength of the dynamically generated Yukawa coupling among composite
fields is calculated. The system of N=1 supersymmetric SU(2) gauge theory with
massive three flavors is considered as an example. We use the techniques of
"integrating in" the gluino-gluino bound state in the low energy effective
theory and the i... | 9901257v2 |
1999-01-18 | Topological inflation induced by a non-minimally coupled massive scalar field | We reanalyze cosmology of a non-minimally coupled massive scalar field which
was originally discussed by Futamase and Maeda in the context of chaotic
inflation scenario. We find a new type of inflationary solution where inflation
occurs inside a domain wall. This new solution relaxes constraints on the
coupling constan... | 9901336v2 |
1999-02-09 | QCD Anomaly Coupling for the $η'-g-g$ Vertex in Inclusive Decay $B\toη' X_s$ | The QCD anomaly coupling of $\eta'-g-g$ is treated as the axial vector
current triangle anomaly. By assuming the divergent axial vector coupling of
the $\eta'$ meson with the quark line in the triangle diagram, we calculate the
QCD anomaly of $\eta'-g-g$ as well as the QED anomaly of $\eta'-\gamma-\gamma$
with only one... | 9902275v1 |
1999-03-17 | Second Loop Corrections from Superheavy Gauge Sector to Gauge Coupling Unification | We deal with extensions of the Standard Model by adding horizontal
interactions between particle generations. We calculate two loop corrections
caused by the presence of coupling between hypothetical horizontal gauge bosons
and matter fields, both at low and high energy. It is proved numerically, that
the coupling of s... | 9903373v2 |
1999-03-18 | Analysis of tbW and ttZ couplings from CLEO and LEP/SLC data | We update the constraints on anomalous dimension four $\tbw$ and $\ttz$
couplings by using CLEO $b \ra s \gamma$ and LEP/SLC precision $Z$-pole data.
It is found that the data imposes very stringent bounds on them. Moreover, the
$2 \sigma$ pull from SM predictions of $A_{LR}$(hadrons), $A_b$ and $A_{FB}$(b)
have little... | 9903394v1 |
1999-03-29 | The renormalized gauge coupling and non-perturbative tests of dimensional reduction | In 4d lattice simulations of Standard Model like theories, the renormalized
gauge coupling in the broken phase can be determined from the prefactor of the
Yukawa term in the static potential. We compute the same quantity in terms of
the conventional MSbar scheme gauge coupling. The result allows for a further
non-pertu... | 9903513v2 |
1999-04-23 | Probing anomalous right--handed current in Z b bbar vertex | Motivated by $-2 \sigma$ deviation from the Standard Model prediction for the
forward--backward asymmetry of $Z \to b \bar{b}$ decay in the LEP data, we
explore the anomalous couplings of $Z b \bar{b}$ vertex through the electroweak
precision test extended by including $A_{FB}^b$. We introduce a new variable
$\epsilon'... | 9904435v1 |
1999-05-17 | The effect of R parity violating couplings on e^-e^-->{\tilde e}_L {\tilde e}_R | In this work we study the effect of R parity breaking couplings on the
process e^-e^-->{\tilde e}_L{\tilde e}_R. We find that an e^-e^- linear
collider opearting at a center of mass energy of 500 Gev with a luminosity of
50 fb^{-1} will be able to probe the coupling
[\lambda_{211}+\lambda_{311}]^{1/2} down to .045 for ... | 9905364v1 |
1999-05-19 | New Limits on the Couplings of Light Pseudoscalars from Equivalence Experiments | The exchange of light pseudoscalar quanta between fermions leads to
long-range spin-dependent forces in order g^2, where g is the
pseudoscalar-fermion coupling constant. We demonstrate that laboratory bounds
on the Yukawa couplings of pseudoscalars to nucleons can be significantly
improved using results from recent equ... | 9905408v1 |
1999-06-04 | Approximate Analytic Solutions of RG Equations for Yukawa and Soft Couplings in SUSY Models | We present simple analytical formulae which describe solutions of the RG
equations for Yukawa couplings in SUSY gauge theories with the accuracy of a
few per cent. Performing the Grassmannian expansion in these solutions one
finds those for all the soft couplings and masses. The solutions clearly
exhibit the fixed poin... | 9906256v3 |
1999-06-10 | Running Coupling BFKL Equation and Deep Inelastic Scattering | I examine the form of the solution of the BFKL equation with running coupling
relevant for deep inelastic scattering. The evolution of structure functions is
precisely determined and well described by an effective coupling of the form
1/(beta_0(ln(Q^2/Lambda^2)+3.6(alpha_s(Q^2)ln(1/x))^1/2)) (until very small x).
Corre... | 9906323v1 |
1999-06-16 | Constraints on the R-parity Violating Couplings from $B^\pm \to l^\pm ν$ Decays | We derive the upper bounds on certain products of R-parity- and
lepton-flavor-violating couplings from $B^\pm \to l^\pm \nu$ decays. These
modes of B-meson decays can constrain the product combinations of the couplings
with one or more heavy generation indices which are comparable with or stronger
than the present boun... | 9906385v1 |
1999-06-16 | Coupled-Channel Final-State Interactions through Reggeon Exchange for D(B) --> ππ, K \bar{K} | Coupled-channel final-state-interaction effects for D and B weak decays into
\pi \pi and K \bar{K} are discussed in a Regge framework. It is found that the
inclusion of coupled-channel effects significantly affects the results obtained
previously in a quasi-elastic approximation. It is also shown that in the
isospin I=... | 9906396v1 |
1999-07-05 | Anomalous Quartic Couplings in $ν\barν γγ$ Production via WW-Fusion at LEP2 | The production of $\nu \bar{\nu} \gamma \gamma$ in high-energy $e^+e^-$
collisions offers a window on anomalous quartic gauge boson couplings. We
investigate the effect of two possible anomalous couplings on the cross section
for $\nu \bar{\nu} \gamma \gamma$ production via $WW$-fusion at LEP2 ($\sqrt{s}
= 200$ GeV). | 9907235v2 |
1999-07-06 | RG invariant solutions for the soft supersymmetry breaking parameters | We show that the results for the soft couplings in supersymmetric gauge
theories recently derived via the superconformal anomaly are equivalent to
results obtained earlier from a consideration of exact RG-invariant
trajectories. We give a full proof of these results for a general
multi-coupling theory. Moreover, we dem... | 9907255v2 |
1999-07-16 | Polarization Asymmetries in $γe$ Collisions and Triple Gauge Boson Couplings Revisited | The capability of the NLC run in the $\gamma e$ collision mode to probe the
CP-conserving $\gamma WW$ and $\gamma ZZ$ anomalous couplings through the use
of the polarization asymmetry is reviewed. When combined with other
measurements, very strong constraints on both varieties of anomalous couplings
can be obtained. We... | 9907395v1 |
1999-08-04 | Bosonic Quartic Couplings at LEP2 | We list the set of C and P conserving anomalous quartic vector bosons
self-couplings which can be tested at LEP2 through triple vector boson
production. We show how this set can be embedded in manifestly SU(2)xU(1) gauge
invariant operators exhibiting an SU(2)_c global symmetry. We derive bounds on
these various coupli... | 9908254v1 |
1999-10-26 | Strong interactions of weak bosons | We discuss the parameterization for electroweak gauge boson interactions
without a light Higgs boson. We present the constraints on the anomalous
gauge-boson couplings from the current experiments. We emphasize that the
four-point couplings involving the longitudinal weak bosons are genuine to the
underlying strong dyn... | 9910495v1 |
1999-12-08 | Low energy effects of Higgs induced leptoquark-diquark mixing | In low energy phenomenology to avoid the strong constraints of proton decay
it is usually assumed that light ($\approx $ 250 Gev) leptoquarks couple only
to quark-lepton pairs and light diquarks couple only to quark pairs. In this
work we show that the SM Higgs boson could induce a mixing between leptoquarks
and diquar... | 9912269v1 |
1999-12-14 | Infrared Fixed Points for Ratios of Couplings in the Chiral Lagrangian | In the framework of the low energy Chiral Lagrangian, the renormalization
group equations for the couplings are investigated up to order p^6, both for
the SU(2) as for the SU(3) cases. Infrared attractive fixed points for ratios
of couplings are found. These fixed points solutions turn out to agree with the
values dete... | 9912335v2 |
1999-12-21 | Constraints on Couplings of Extra Gauge Bosons from e+e- --> nu nubar gamma | If extra gauge bosons are observed at the LHC or at a linear e+e- collider,
the reaction e+e- --> nu nubar gamma can give information on the couplings (W'
nu l) and (Z' nu nubar). The total cross section and polarization asymmetries
are the most sensitive observables for such a measurement. Small systematic
errors are ... | 9912444v1 |
1999-12-28 | Radiative Splitting of Three Degenerate Neutrinos | We propose a radiative origin of the two mass splittings of three degenerate
Majorana neutrinos. It can be achieved by extending the standard model to have
the usual effective dimension 5 operators generating SO(3)-invariant tree-level
masses, and a charged scalar singlet coupling with the leptons preserving the
U(1) s... | 9912524v1 |
2000-01-10 | Matter effects on neutrino oscillations in gravitational and magnetic fields | When neutrinos propagate in a background, their gravitational couplings are
modified by their weak interactions with the particles in the background. In a
medium that contains electrons but no muons or taons, the matter-induced
gravitational couplings of neutrinos are different for the various neutrino
flavors, and the... | 0001069v1 |
2000-01-17 | The Reconstruction of Trilinear Higgs Couplings | To establish the Higgs mechanism {\it sui generis} experimentally, the Higgs
self-interaction potential must be reconstructed. This task requires the
measurement of the trilinear and quadrilinear self-couplings, as predicted in
the Standard Model or in supersymmetric theories. The couplings can be probed
in multiple Hi... | 0001169v1 |
2000-02-03 | Measuring Higgs boson couplings at the LHC | For an intermediate mass Higgs boson with SM-like couplings the LHC allows
observation of a variety of decay channels in production by gluon fusion and
weak boson fusion. Cross section ratios provide measurements of various ratios
of Higgs couplings, with accuracies of order 15% for 100 fb^{-1} of data in
each of the t... | 0002036v1 |
2000-02-09 | Constraints on a Model with Pure Right-Handed Third Generation Couplings | We examine constraints on a model with pure right-handed third generation
charged couplings. The parameters of the right-handed mixing matrix and the
right-handed coupling strength are constrained from semi-leptonic B decays, the
mass difference of neutral mesons, the CP violating observables epsilon and
epsilon', and ... | 0002104v1 |
2000-03-01 | Resonance Production of Three Neutral Supersymmetric Higgs Bosons at LHC | Multiple production of Higgs particles is essential to study Higgs
self-couplings at future high-energy colliders. In this paper we calculated the
resonance contributions to the production of three lightest neutral
supersymmetric Higgs bosons in gluon fusion at LHC. The cross sections due to
trilinear Higgs couplings i... | 0003008v1 |
2000-03-14 | Mesonic Anapole Form Factors of the Nucleons | The chiral quark model posits pseudoscalar and vector meson couplings to
constituent quarks. The parity violating meson-quark couplings lead to anapole
moments and form factors of the nucleons. These arise both as parity violating
meson loop fluctuations as well as exchange currents and polarization currents
that are i... | 0003132v2 |
2000-03-15 | From Black Holes to Pomeron: Tensor Glueball and Pomeron Intercept at Strong Coupling | We briefly review the approach for strong coupling calculation of glueball
masses based on the duality between supergravity and Yang-Mills theory. Earlier
work is extended to non-zero spin. Fluctuations in the gravitational metric
lead to the $2^{++}$ tensor glueball state on the leading Pomeron trajectory
with a mass ... | 0003153v1 |
2000-03-23 | Higgs induced light leptoquark-diquark mixing and proton decay | In low energy phenomenology to avoid the strong constraints of proton decay
it is usually assumed that light ($\approx $ 250 Gev) leptoquarks couple only
to quark-lepton pairs and light diquarks couple only to quark pairs. In this
paper we present two specific examples where the higgs induced mixing between
leptoquarks... | 0003229v1 |
2000-05-29 | A Numerical Analysis to the {$π$} and {K} Coupled--Channel Scalar Form-factor | A numerical analysis to the scalar form-factor in the $\pi\pi$ and KK
coupled--channel system is made by solving the coupled-channel dispersive
integral equations, using the iteration method. The solutions are found not
unique. Physical application to the $\pi\pi$ central production in the $pp\to
pp\pi\pi$ process is d... | 0005284v2 |
2000-06-02 | The spin correlation in top quark production: QCD corrections vs anomalous couplings | We discuss top quark production and its subsequent decay at lepton colliders
including both QCD corrections and anomalous gamma / Z - t t-bar couplings. The
off-diagonal spin basis for the top and anti-top quarks is shown to be useful
to probe the anomalous couplings. | 0006021v1 |
2000-07-06 | Luminosity of Asymmetric e+e- Collider with Coupling Lattices | A formula of luminosity of asymmetric e+e- collider with coupled lattices is
derived explicitly. The calculation shows how the tilted angle and aspect ratio
of the beams affect the luminosity. Knowing the result of the calculation, we
measure the tilted angle of the luminous region of the collision for PEP-II
using two... | 0007052v1 |
2000-08-03 | Three Loop Free Energy Using Screened Perturbation Theory | The conventional weak-coupling expansion for the pressure of a hot plasma
shows no sign of convergence unless the the coupling constant $g$ is tiny. In
this talk, I discuss screened perturbation theory (SPT) which is a
reorganization of the perturbative expansion by adding and subtracting a local
mass term in the Lagra... | 0008027v1 |
2000-08-03 | Critical coupling for chiral symmetry breaking in QCD motivated models | We determine the critical coupling constant above which dynamical chiral
symmetry breaking occurs in a class of QCD motivated models where the gluon
propagator has an enhanced infrared behavior. Using methods of bifurcation
theory we find that the critical value of the coupling constant is always
smaller than the one o... | 0008036v1 |
2000-09-15 | Small Violation of Universal Yukawa Coupling and Neutrino Large Mixing | We assume the universal Yukawa coupling (democratic mass matrix) with small
violations for quarks, charged leptons and neutrinos masses. We could reproduce
the mass hierarchy for quark masses and V_{CKM} matrix elements precisely. We
adopt the see-saw mechanism for the explanation of smallness of neutrino masses
and in... | 0009181v1 |
2000-09-25 | Searching for Anomalous Higgs Couplings in Peripheral Heavy Ion Collisions at the LHC | We investigate the sensitivity of the heavy ion mode of the LHC to anomalous
Higgs boson couplings to photons, H-photon-photon, through the analysis of the
processes photon photon to b anti-b and photon photon to photon photon in
peripheral heavy ion collisions. We suggest cuts to improve the signal over
background rat... | 0009289v2 |
2000-10-25 | Off-shell d=5 Supergravity coupled to Matter-Yang-Mills System | We present an off-shell formulation of matter-Yang-Mills system coupled to
supergravity in five dimensional space-time. We give an invariant action for
the general system of vector multiplets and hypermultiplets coupled to
supergravity as well as the supersymmetry transformation rules. All the
auxiliary fields are kept... | 0010288v2 |
2000-12-22 | Top flavour-changing neutral coupling signals at a linear collider | We present an analysis of the sensitivity of the TESLA e+ e- collider to top
flavour-changing neutral couplings to the Z boson and photon. We consider the
cases without beam polarization, with only e- polarization and with e- and e+
polarization, showing that the use of the latter substantially enhances the
sensitivity... | 0012305v2 |
2001-01-18 | Quantum corrections for the MSSM Higgs couplings to SM fermions | Higgs Yukawa couplings to down-type fermions receive, in the MSSM,
supersymmetric quantum corrections that can be of order 1 for large values of
tan\beta, provided \mu \sim MSUSY. Therefore, a sensitive prediction for
observables driven by any of these couplings can only be obtained after an
all-order resummation of th... | 0101206v1 |
2001-03-09 | Equilibration in an Interacting Field Theory | We use a combination of perturbation theory and numerical techniques to study
the equilibration of two interacting fields which are initially at thermal
equilibrium at different temperatures. Using standard rules of quantum field
theory, we examine the master equations that describe the time evolution of the
distributi... | 0103098v1 |
2001-04-09 | The coupling constant g$_{ρσγ}$ as derived from QCD sum rules | We employ QCD sum rules to calculate the coupling constant
g$_{\rho\sigma\gamma}$ by studying the three point
${\rho\sigma\gamma}$-correlation function. Our results is consistent with the
value of this coupling constant obtained using vector meson dominance of the
electromagnetic current and the experimental $\rho^0$-p... | 0104084v1 |
2001-04-24 | Three loop gauge beta-function for the most general single gauge-coupling theory | We calculate the three loop contribution to the beta-function of the gauge
coupling constant in a general, anomaly-free, renormalisable gauge field theory
involving a single gauge coupling using the background field method in the
MSbar scheme. | 0104247v1 |
2001-05-31 | Nonperturbative Contributions in an Analytic Running Coupling of QCD | In the framework of analytic approach to QCD the nonperturbative
contributions in running coupling of strong interaction up to 4-loop order are
obtained in an explicit form. For all $Q>\Lambda$ they are shown to be
represented in the form of an expansion in inverse powers of Euclidean momentum
squared. The expansion co... | 0105338v1 |
2001-09-17 | Complex flavour couplings in supersymmetry and unexpected CP-violation in the decay B -> phi K | Complex flavour couplings (off-diagonal mass terms) in the squark sector of
supersymmetric theories may drastically alter both the rate and the
CP-violating asymmetry of certain B-meson decays. We consider the effects of
couplings that induce b -> s transitions and lead to final state with
strangeness one. We investiga... | 0109149v1 |
2001-09-24 | Freezing of the QCD coupling constant and solutions of Schwinger-Dyson equations | We compare phenomenological values of the frozen QCD running coupling
constant ($\alpha_s$) with two classes of solutions obtained through
nonperturbative Schwinger-Dyson equations. We use these same solutions with
frozen coupling constants as well as their respective nonperturbative gluon
propagators to compute the QC... | 0109223v2 |
2001-10-10 | A Simple Model for the BFKL-DGLAP Transition in Deep Inelastic Scattering | A simple model is presented, which interpolates between the DGLAP and BFKL
regimes in deep inelastic e-p scattering. The model is based on the CCFM and
LDC models, and it is simple enough to provide an intuitive picture of the
transition region between the two domains. Results are presented for both fixed
and running c... | 0110143v1 |
2001-10-21 | Associated t anti-t H production at a VLHC: measuring the top-quark Yukawa coupling | Future hadron colliders will have the potential to measure some of the most
relevant Higgs boson couplings with high precision. In this paper we
investigate the potential of a Very Large Hadron Collider (VLHC) to measure the
top-quark Yukawa coupling. | 0110274v2 |
2001-10-23 | Lepton Flavor Changing Neutral Current Processes at Lepton-Hadron Colliders | We investigate the potentials of high energy lepton-proton colliders to
detect a flavor changing $l-l^{\prime}-Z$ or $l-l^{\prime}-\gamma$ couplings
from the processes $ep\to\mu(\tau)X$ and $\mu p\to \tau X$. For the
$l-l^{\prime}-Z$ coupling we consider string inspired $E_6$ model whereas
$l-l^{\prime}-\gamma$ couplin... | 0110294v3 |
2001-10-31 | Precise predictions for e+e- --> 4f(+gamma) with anomalous couplings | The relevance of radiative corrections to 4f production at LEP2 and future
e+e- colliders is emphasized, and their treatment in the event generator
RacoonWW is briefly discussed. In particular, the non-universal corrections are
compared with the signature of anomalous triple gauge-boson couplings. For
4f+gamma producti... | 0110402v1 |
2002-01-18 | Experimental tests of curvature couplings of Fermions in General Relativity | Spin 1/2 particles in geodesic trajectories experience no gravitational
potential but they still have non-zero couplings to the curvature tensor. The
effect of space time curvature on fermions can be parameterized by a vector and
a pseudo-vector potential. These apparent CPT violating terms can be measured
with satelli... | 0201172v2 |
2002-05-15 | Fresh inflation with nonminimally coupled inflaton field | I study a fresh inflationary model with a scalar field nonminimally coupled
to gravity. An example is examined. I find that, as larger is the value of $p$
(the power of the scale factor), smaller (but larger in its absolute value) is
the necessary value of the coupling $\xi$ to the inflaton field fluctuations
can satis... | 0205171v2 |
2002-05-30 | On universality of the coupling of neutrinos to Z | We employ an effective Lagrangian approach and use LEP data to place severe
bounds on universality violations of the couplings of $\nu_e$, $\nu_\mu$, and
$\nu_\tau$ to the $Z$ boson. Our results justify the assumption of universality
in these couplings that is usually made, as for example in the analysis of
solar neutr... | 0205335v2 |
2002-06-19 | Re-analysis of the $D^* Dπ$ coupling in the light-cone QCD sum rules | The recent measurement from the CLEO experiment presents the $DD^*\pi$
coupling, $17.9\pm 0.3 \pm 1.9$. This value is much larger than any of QCD sum
rule predictions available in literature. We report that, with a relevant
treatment of the continuum subtraction as well as with the asymptotic form of
the twist-2 pion w... | 0206170v2 |
2002-07-23 | Testing coupling relations in SUSY-QCD at a Linear Collider | Supersymmetry predicts that gauge couplings are equal to the corresponding
gaugino-sfermion-fermion Yukawa couplings. This prediction can be tested for
the QCD sector of the MSSM by studying the processes eplus+eminus ->
squark+antisquark+gluon and eplus+eminus -> squark+antiquark+gluino at a future
linear collider. We... | 0207278v1 |
2002-08-27 | Axial Vector Current and Coupling of the Quark in the Instanton Model | We compute the axial vector current, form factor, and coupling for quarks in
the instanton liquid model with two light flavors. Non-local current
corrections are derived, as required by the effective 't Hooft interaction. We
obtain a pion-mediated axial form factor and an axial coupling which, when
simply applied in th... | 0208250v3 |
2002-10-31 | Gell-Mann - Low Function for QCD in the strong-coupling limit | The Gell-Mann - Low function \beta(g) in QCD (g=g0^2/16\pi^2 where g0 is the
coupling constant in the Lagrangian) is shown to behave in the strong-coupling
region as \beta_\infty g^\alpha with \alpha\approx -13, \beta_\infty\sim 10^5. | 0210439v2 |
2002-11-05 | Measurement of the Higgs self-coupling at JLC | We examine the double Higgs production process at JLC. We focus our attention
on the measurement of the Higgs self-coupling. The sensitivity of the triple
Higgs coupling measurement is discussed in the Higgs mass range 100-200 GeV and
the center of mass energy to be 500 GeV-1.5 TeV. | 0211047v2 |
2002-11-10 | Rare decay Z --> neutrino antineutrino photon photon via quartic gauge boson couplings | We present a detailed calculation of the rare decay Z --> neutrino
antineutrino photon photon via the quartic neutral gauge boson coupling
Z-Z-photon-photon in the framework of the effective Lagrangian approach. The
current experimental bound on this decay mode is then used to constrain the
coefficients of this couplin... | 0211135v1 |
2002-11-27 | A Note on the J/psi Strong Couplings | In this note we present an evaluation of the couplings JD(*)D(*) and
JD(*)D(*)pi in the Constituent Quark Model. These couplings are a crucial
ingredient in the calculation of cross sections for the processes pi J/psi ->
D(*)Dbar(*), an important background for the J/psi suppression signal in
quark-gluon plasma. | 0211431v1 |
2002-12-13 | String corrections to gauge couplings from a field theory approach | An effective field theory approach is introduced to compute one-loop
radiative corrections to the gauge couplings due to Kaluza-Klein states
associated with a two-torus compactification. The results are compared with
those of the string in the field theory ``limit'' alpha'-> 0. The whole U and
the leading T moduli depe... | 0212197v2 |
2002-12-16 | Non-minimally Coupled Tachyon and Inflation | In this paper, we consider a model of tachyon with a non-minimal coupling to
gravity and study its cosmological effects. Regarding inflation we will show
that for a specific coupling of tachyon to gravity this model satisfies
observations and solves various problems which exist in the single and multi
tachyon inflation... | 0212219v1 |
2003-01-12 | Determination of the numerical value for the strong coupling constant from tau decays in perturbative QCD | The determination of the numerical value for the strong coupling constant
from tau decays in perturbative QCD is briefly described. Main emphasis is made
on the use of the renormalization scheme invariance of the theory for reducing
uncertainties related to truncation of the series in the strong coupling
constant. The ... | 0301074v1 |
2003-01-19 | Spin-5/2 resonance effects in a coupled channel nucleon resonance analysis | Spin-$\ffh$ resonance contributions in pion-nucleon scattering are
investigated within the coupled channel $K$-matrix approach for c.m. energies
up to $\sqrt s=$ 2 GeV. All previously studied $\pi N$, $2\pi N$, $\eta N$, $K
\Lambda$, $K \Sigma$, and $\omega N$ final states are included. We find a
significant improvemen... | 0301152v1 |
2003-02-17 | ZZH coupling : A probe to the origin of EWSB ? | We argue that the $ZZH$ coupling constitutes a simple probe of the nature of
the scalar sector responsible for electroweak symmetry breaking. We demonstrate
the efficacy of this measure through an analysis of four-dimensional models
containing scalars in arbitrary representation of $SU(2) \times U(1)$, as well
as extra... | 0302141v2 |
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