publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
|---|---|---|---|
1997-07-25 | Single top quark production as a probe of R-parity-violating SUSY at pp and p\bar p colliders | We investigate the ability of single top quark production via qq'->
squark->tb and q \bar q'->slepton->t\bar b at the LHC and Tevatron to probe the
strength of R-parity violating couplings in the minimal supersymmetric model.
We found that given the existing bounds on R-parity violating couplings, single
top quark prod... | 9707477v1 |
1998-01-20 | Suppression of Pi NN* Coupling and Chiral Symmetry | Meson-baryon couplings between positive and negative parity nucleons are
investigated using two point correlation functions in the soft meson and the
chiral limit. We find that the pi NN* coupling vanishes due to chiral symmetry,
while the eta NN* coupling remains finite. We perform an analysis based on the
algebraic m... | 9801354v1 |
1998-04-21 | Probing anomalous top quark couplings at eγcolliders | We study in the effective Lagrangian approach the possibility of probing
anomalous top quark charged current couplings in the single top production at a
high energy e\gamma collider. We analyzed all possible dimension-six
CP-conserving operators which can give rise to an anomalous Wtb coupling which
represent new physi... | 9804343v2 |
1998-04-21 | CP Violation, Higgs Couplings, and Supersymmetry | Supersymmetric extensions of the standard model generically contain
additional sources of CP violation. We discuss how at one loop a potentially
large CP violating coupling of the lightest Higgs, h^0, to leptons is induced
in the minimal supersymmetric standard model (MSSM). The CP violating couplings
of h^0 in extensi... | 9804355v2 |
1998-04-28 | The effect of Yukawa couplings on Unification Predictions and the non-perturbative limit | We investigate the effects of Yukawa couplings on the phenomenological
predictions for a class of supersymmetric models which allows for the presence
of complete SU(5) multiplets in addition to the Minimal Supersymmetric Standard
Model spectrum. We develop a two loop analytical approach to quantify the
predictions for ... | 9804437v2 |
1998-06-12 | Triple Gauge Boson Couplings in Rare B and K Decays | We examine the sensitivity of flavor changing neutral current (FCNC)
processes to anomalous triple gauge boson couplings. We show that in the
non-linear realization of the electroweak symmetry breaking sector these
processes are very sensitive to two CP conserving anomalous couplings. A clean
separation of their effect... | 9806360v3 |
1998-06-25 | Single Top Quark Production via FCNC Couplings at Hadron Colliders | We calculate single top-quark production at hadron colliders via the
chromo-magnetic flavor-changing neutral current couplings $\bar tcg$ and $\bar
tug$. We find that the strength for the anomalous $\bar tcg$ ($\bar tug$)
coupling may be probed to $\kappa_c / \Lambda = 0.092 {TeV}^{-1}$ ($\kappa_u /
\Lambda = 0.026 {Te... | 9806486v1 |
1998-09-01 | CP-violating Z-gamma-gamma and top-quark electric dipole couplings in gamma gamma -> t bar{t} | An effective anomalous CP-violating Z-gamma-gamma coupling can give rise to
observable CP-odd effects in gamma gamma -> t bar{t}. We study certain
asymmetries in the decay lepton distributions in gamma gamma -> t bar{t}
arising from top decay in the presence of a CP-violating Z-gamma-gamma coupling
as well as a top-qua... | 9809203v2 |
1999-03-19 | Yukawa coupling corrections to stop, sbottom, and stau production in e+ e- annihilation | We calculate within the MSSM the one-loop Yukawa coupling corrections to the
processes e+ e- \to stops, sbottoms, and staus in order of Yukawa coupling
squared. These corrections are due to the exchange of charginos, neutralinos,
charged and neutral Higgs bosons, and charged and neutral Higgs ghosts. We give
the comple... | 9903413v1 |
1999-07-06 | String theoretic axion coupling and the evolution of cosmic structures | We examine the effects of the axion coupling to $R\tilde{R}$ on the evolution
of cosmic structures. It is shown that the evolutions of the scalar- and
vector-type perturbations are not affected by this axion coupling. However the
axion coupling causes an asymmetric evolution of the two polarization states of
the tensor... | 9907244v1 |
1999-07-29 | Dimensionless supersymmetry breaking couplings, flat directions, and the origin of intermediate mass scales | The effects of supersymmetry breaking are usually parameterized by soft
couplings of positive mass dimensions. However, realistic models also predict
the existence of suppressed, but non-vanishing, dimensionless
supersymmetry-breaking couplings. These couplings are technically hard, but do
not lead to disastrous quadra... | 9907550v1 |
1999-08-31 | Anomaly-Induced Gauge Unification and Brane/Bulk Couplings in Gravity-Localized Theories | It has recently been proposed that gravity-localized compactifications can
generate the required gauge hierarchy without the need for hierarchically large
extra spacetime dimensions. In this paper, we show that gauge coupling
unification arises naturally in such scenarios as a result of the anomaly
induced by the resca... | 9908530v1 |
1999-09-06 | Masses and Couplings of the Lightest Higgs Bosons in the (M+1)SSM | We study the upper limits on the mass of the lightest and second lightest CP
even Higgs bosons in the (M+1)SSM, the MSSM extended by a gauge singlet. The
dominant two loop contributions to the effective potential are included, which
reduce the Higgs masses by 10 GeV. Since the coupling R of the lightest Higgs
scalar to... | 9909260v2 |
1999-10-05 | Dynamical generation of the gauged SU(2) linear sigma model | The fermion and meson sectors of the quark-level SU(2) linear sigma model are
dynamically generated from a meson-quark Lagrangian, with the quark (q) and
meson ($\sigma,\pi$) fields all treated as elementary, having neither bare
masses nor expectation values. In the chiral limit, the masses are predicted to
be $m_q = f... | 9910242v1 |
2000-02-03 | Prospects of Measuring General Higgs Couplings at e^+e^- Linear Colliders | We examine how accurately the general HZV couplings, with V=Z,gamma, may be
determined by studying e^+e^- --> Hff-bar processes at future e^+e^- linear
colliders. By using the optimal-observable method, which makes use of all
available experimental information, we find out which combinations of the
various HZV coupling... | 0002043v1 |
2000-02-09 | Yukawa hierarchy from extra dimensions and infrared fixed points | We discuss the existence of hierarchy of Yukawa couplings in the models with
extra spatial dimensions. The hierarchical structure is induced by the power
behavior of the cutoff dependence of the evolution equations which yield large
suppressions of couplings at the compactification scale. The values of coupling
constan... | 0002102v2 |
2000-02-16 | A method for determining anomalous gauge boson couplings from e^{+}e^{-} experiments | We present a model-independent method for determining anomalous gauge boson
couplings from ongoing and future e^{+}e^{-} -> W^{+} W^{-} experiments. First
we generalize an already existing method, which relies on the study of four
observables constructed through appropriate projections of the unpolarized
differential c... | 0002176v1 |
2000-02-28 | Right-Handed Vector V and Axial A Couplings in Weak Interactions | In this paper a scenario admitting the participation of right-handed vector V
and axial A couplings with the conservation of the left-handed standard (V, A)
couplings is considered. The research is based on the muon capture by proton.
We consider muon capture at the level of the Fermi theory (four-fermion point
interac... | 0002289v2 |
2000-03-03 | On the $η$ and f$_1$(1420) Couplings to the Nucleon | We consider neutral pseudoscalar, $\eta $, and axial vector, $f_1(1420)$,
mesons in the OZI-rule-respecting flavor basis, $\lbrace (\bar s s), {1\over
\sqrt{2}}(\bar u u + \bar d d)\rbrace$, and suggest a scenario for their
coupling to the nucleon. Within this framework, the non--strange parts of the
$\eta N$ and f$_1 ... | 0003023v1 |
2000-03-15 | New and Standard Physics contributions to anomalous Z and gamma self-couplings | We examine the Standard and the New Physics (NP) contributions to the ZZZ,
ZZgamma and Zgammagamma neutral gauge couplings. At the one-loop level, if we
assume that there is no CP violation contained in NP beyond the Standard Model
one, we find that only CP conserving neutral gauge couplings are generated,
either from ... | 0003143v1 |
2000-06-19 | Higgs masses and couplings in the NMSSM | We give the upper bounds on the masses of the lightest and second lightest CP
even Higgs bosons in the NMSSM, the MSSM extended by a gauge singlet. The
dominant two loop corrections are included. Since the coupling R of the
lightest Higgs scalar to gauge bosons can be small, we study in detail the
relation between mass... | 0006222v1 |
2000-08-11 | Couplings of a Light Dilaton and Violations of the Equivalence Principle | Experimental discovery of the dilaton would provide strong evidence for
string theory. A light dilaton could show up in current tests of the inverse
square law for gravity at sub-millimeter distances. In the large extra
dimension scenario, Kaluza-Klein excitations of the dilaton can also contribute
to the cooling of su... | 0008116v1 |
2001-04-05 | Probing anomalous quartic gauge-boson couplings via e+e- --> 4fermions+gamma | All lowest-order amplitudes for e+e- --> 4f+gamma are calculated including
five anomalous quartic gauge-boson couplings that are allowed by
electromagnetic gauge invariance and the custodial SU(2)_c symmetry. Three of
these anomalous couplings correspond to the operators L_0, L_c, and L_n that
have been constrained by ... | 0104057v2 |
2001-06-06 | Computing the perturbative gluon condensate | The normalization of the gluon condensate and of renormalon-related power
corrections in QCD is computed under the assumption that their ``perturbative''
part dominates over any eventual extra contribution from the non-trivial
vacuum. The calculation is performed in the infrared finite coupling framework,
assuming an i... | 0106070v2 |
2001-06-13 | On Testing for New Couplings in Top Quark Decay | To quantitatively assay future measurements of competing observables in t -->
W b decay, we consider the g_{V-A} coupling values of the helicity decay
parameters versus those for "(V-A)+ Single Additional Lorentz Structures".
There are 2 dynamical phase-type ambiguities. Associated with the latter (f_M +
f_E) ambiguity... | 0106137v1 |
2001-06-27 | Extracting the Flavour Structure of a Baryon-Number R-parity Violating Coupling at the LHC | The detection of the flavour content of jets produced from R-parity violating
neutralino decays is investigated in the case where one baryon-number violating
coupling dominates. Simulations are performed of the ATLAS experiment at the
LHC for all couplings, other than lambda"_tjk since neutralino decays through
these c... | 0106304v1 |
2001-09-20 | Factorization and Resummation of Small x Scaling Violations with Running Coupling | We discuss the inclusion of running coupling effects in perturbative small x
evolution equations. We show that a running coupling BFKL-like x-evolution
equation is fully compatible, up to higher twist corrections, with the standard
factorized perturbative evolution of parton distributions. We then use this
result, comb... | 0109178v1 |
2001-09-28 | Loop induced Higgs and Z boson couplings to Neutralinos and implications for collider and Dark Matter searches | We calculate the one-loop induced couplings of two gaugino-like neutralinos
to the $Z$ and Higgs bosons in the Minimal Supersymmetric Standard Model. These
couplings, which vanish at the tree level, can be generated through loops
involving fermions and sfermions. We show that, while the neutralino
contribution to the i... | 0109283v2 |
2001-10-28 | Infrared quasi-fixed solutions in the NMSSM | The considerable part of the parameter space in the MSSM corresponding to the
infrared quasi fixed point scenario is almost excluded by LEP II bounds on the
lightest Higgs boson mass. In the NMSSM the mass of the lightest Higgs boson
reaches its maximum value in the strong Yukawa coupling limit when Yukawa
couplings ar... | 0110363v1 |
2001-11-08 | Couplings between pion and charmed mesons | We compute the couplings $DD^*\pi$,$D_1D^*\pi$,$D^*D^*\pi$, $D_1 D_1\pi$
using QCD sum rules. These couplings are important inputs in the meson exchange
model calculations used to estimate the amount of $J/\psi$ absorption due to
pions and rho mesons in heavy ion collisions. Our sum rules are constructed at
the first o... | 0111087v1 |
2001-12-24 | Triple Neutral Gauge Boson Couplings in Noncommutative Standard Model | It has been shown recently that the triple neutral gauge boson couplings are
not uniquely determined in noncommutative extension of the Standard Model
(NCSM). Depending on specific schemes used, the couplings are different and may
even be zero. To distinguish different realizations of the NCSM, additional
information e... | 0112320v1 |
2001-12-28 | Infrared Quasi Fixed Point Structure in Extended Yukawa Sectors and Application to R-parity Violation | We investigate one-loop renormalization group evolutions of extended sectors
of Yukawa type couplings. It is shown that Landau Poles which usually provide
necessary low energy upper bounds that saturate quickly with increasing initial
value conditions, lead in some cases to the opposite behaviour: some of the low
energ... | 0112353v1 |
2002-03-01 | Constraining the variation of the coupling constants with big bang nucleosynthesis | We consider the possibility of the coupling constants of the $SU(3)\times
SU(2)\times U(1)$ gauge interactions at the time of big bang nucleosynthesis
having taken different values from what we measure at present, and investigate
the allowed difference requiring the shift in the coupling constants not
violate the succe... | 0203006v1 |
2002-03-18 | Neutrino masses and unification of the gauge and Yukawa couplings | There is a convincing experimental evidence that neutrinos are massive.
Therefore we investigate the influence of the neutrino masses on the
unification of gauge and Yukawa couplings in the framework of the Minimal
Supersymmetric Standard Model. We estimate the contribution of the neutrino
Yukawa coupling to the gauge ... | 0203168v3 |
2002-04-19 | The Coupling of eta Mesons to Quarks and Baryons from D_s^* -> D_s pi^0 Decay | The known ratio of the branching fractions for D_s^* --> D_s pi^0 and D_s^*
--> D_s gamma may be used to extract the coupling of eta mesons to strange
quarks once the value of the pi^0-eta mixing angle is known. This requires that
realistic models for the spectra as well as the magnetic dipole (M1) decays of
the heavy-... | 0204230v2 |
2002-04-26 | Probing anomalous right-handed top quark couplings in rare B decays | We explore the anomalous right-handed $\bar{t}sW$ and $\bar{t}bW$ couplings
using $ B \to X_s \gamma$ and $B \to X_s l^+ l^-$ decays induced by the
flavour-changing penguin diagrams. The anomalous $\bar{t}sW$ coupling can yield
10% enhancement of the $B \to X_s l^+ l^-$ decay rate under the constraint from
the present ... | 0204303v4 |
2002-05-08 | Yukawa Hierarchy Transfer Based on Superconformal Dynamics and Geometrical Realization in String Models | We propose a scenario that leads to hierarchical Yukawa couplings and
degenerate sfermion masses at the same time, in the context of
extra-dimensional models, which can be naturally embedded in a wide class of
string models. The hierarchy of Yukawa couplings and degeneracy of sfermion
masses can be realized thanks to s... | 0205071v1 |
2002-05-22 | Phenomenology of A Three-Family Standard-like String Model | We discuss the phenomenology of a three-family supersymmetric Standard-like
Model derived from the orientifold construction, in which the ordinary chiral
states are localized at the intersection of branes at angles. In addition to
the Standard Model group, there are two additional U(1)' symmetries, one of
which has fam... | 0205252v2 |
2002-07-01 | Radius-dependent gauge unification in AdS5 | We examine the relation of the 4-dimensional low energy coupling of bulk
gauge boson in a slice of AdS5 to the 5-dimensional fundamental couplings as a
function of the orbifold radius R. This allows us to address the gauge coupling
unification in AdS5 by means of the radius running as well as the conventional
momentum ... | 0207013v3 |
2002-08-09 | Phenomenological tests for the freezing of the QCD running coupling constant | We discuss phenomenological tests for the frozen infrared behavior of the
running coupling constant and gluon propagators found in some solutions of
Schwinger-Dyson equations of the gluonic sector of QCD. We verify that several
observables can be used in order to select the different expressions of alpha_s
found in the... | 0208095v2 |
2002-09-12 | Time Variations in the Scale of Grand Unification | We study the consequences of time variations in the scale of grand
unification, $M_U$, when the Planck scale and the value of the unified coupling
at the Planck scale are held fixed. We show that the relation between the
variations of the low energy gauge couplings is highly model dependent. It is
even possible, in pri... | 0209134v2 |
2002-10-07 | Decoupling behaviour of O(m_t^4) corrections to the h^0 self-couplings | The decoupling behaviour of the leading one-loop Yukawa-coupling
contributions of O(m_t^4) to the lightest MSSM Higgs boson self-couplings, when
the top-squarks are heavy as compared to the electroweak scale, are discussed.
As shown analytically and numerically, the large corrections can almost
completely be absorbed i... | 0210108v3 |
2002-10-08 | Calculating the pion decay constant from α_s(M_Z) | We revisit the analysis of the improved ladder Schwinger-Dyson (SD) equation
for the dynamical chiral symmetry breaking in QCD with emphasizing the
importance of the scale ambiguity. Previous calculation done so far naively
used one-loop MSbar coupling in the improved ladder SD equation without
examining the scale ambi... | 0210115v1 |
2002-11-24 | Bounds on the Coupling of the Majoron to Light Neutrinos from Supernova Cooling | We explore the role of Majoron ($J$) emission in the supernova cooling
process, as a source of upper bound on neutrino-Majoron coupling.
We show that the strongest upper bound on the coupling to $\nu_e$ comes from
the $\nu_e\nu_e \to J $ process in the core of a supernova. We also find bounds
on diagonal couplings of... | 0211375v3 |
2003-01-15 | Nuclear A-dependence near the Saturation Boundary | The A-dependence of the saturation momentum and the scaling behavior of the
scattering of a small dipole on a nuclear target are studied in the
McLerran-Venugopalan model, in fixed coupling BFKL dynamics and in running
coupling BFKL dynamics. In each case, we find scaling not too far from the
saturation boundary, altho... | 0301109v1 |
2003-01-24 | Excited Baryons in Large N_c QCD Revisited: The Resonance Picture Versus Single-Quark Excitations | We analyze excited baryon properties via a 1/N_c expansion from two
perspectives: as resonances in meson-nucleon scattering, and as single-quark
excitations in the context of a simple quark model. For both types of analysis
one can derive novel patterns of degeneracy that emerge as N_c --> \infty, and
that are shown to... | 0301219v1 |
2003-09-30 | Lower limits on R-parity-violating couplings in supersymmetric models with light squarks | We interpret the results of searches for strongly interacting massive
particles to place absolute lower limits on R-parity-violating couplings for
squarks with mass (m_\tilde{q}) below 100 GeV. Recent searches for anomalous
isotopes require that there be a baryon-number-violating or
lepton-number-violating coupling lar... | 0310001v2 |
2003-10-14 | Probing Anomalous Top-Quark Couplings Induced by Dim.6 Operators at Photon Colliders | Possible anomalous top-quark couplings induced by SU(2) x U(1)
gauge-invariant dimension-6 effective operators were studied in the process of
t t-bar productions and decays at polarized gamma gamma colliders. Two
CP-violating asymmetries, a linear-polarization asymmetry and a
circular-polarization asymmetry, were compu... | 0310159v3 |
2003-12-03 | Toward understanding the lattice QCD results from the strong coupling analysis | This is a review of strong coupling approaches to grasp the nature of the
phase transition in finite temperature and density QCD. We commence with
classics of the center symmetry and the Polyakov loop in pure gauge theories.
The effective action derived in the strong coupling limit gives qualitatively
plausible behavio... | 0312057v1 |
2003-12-16 | Why does the Quark-Gluon Plasma at RHIC behave as a nearly ideal fluid ? | The lecture is a brief review of the following topics: (i) collective flow
phenomena in heavy ion collisions. The data from RHIC indicate robust
collective flows, well described by hydrodynamics with expected Equation of
State. The transport properties turned out to be unexpected, with very small
viscosity;
(ii) phys... | 0312227v2 |
2004-01-22 | Instantons and the Spin of the Nucleon | Motivated by measurements of the flavor singlet axial coupling constant of
the nucleon in polarized deep inelastic scattering we study the contribution of
instantons to OZI violation in the axial-vector channel. We consider, in
particular, the f_1-a_1 meson splitting, the flavor singlet and triplet axial
coupling of a ... | 0401165v2 |
2004-03-31 | The NuTeV Anomaly, Lepton Universality, and Non-Universal Neutrino-Gauge Couplings | In previous studies we found that models with flavor-universal suppression of
the neutrino-gauge couplings are compatible with NuTeV and Z-pole data. In this
paper we expand our analysis to obtain constraints on flavor-dependent coupling
suppression by including lepton universality data from W, tau, pi and K decays
in ... | 0403306v2 |
2004-07-16 | Dimensionless Coupling of Bulk Scalars at the LHC | We identify the lowest-dimension interaction which is possible between
Standard Model brane fields and bulk scalars in 6 dimensions. The
lowest-dimension interaction is unique and involves a trilinear coupling
between the Standard Model Higgs and the bulk scalar. Because this interaction
has a dimensionless coupling, i... | 0407196v1 |
2004-08-08 | Bounds on the Higgs Mass in Variations of Split Supersymmetry | We investigate the limits on the higgs mass in variations of Split
Supersymmetry, where the boundary value of the Higgs quartic coupling at the
SUSY breaking scale ($m_s$) is allowed to deviate from its value in the minimal
model of Arkani-Hamed and Dimopoulos. We show that it is possible for
$\lambda(m_s)$ to be negat... | 0408096v1 |
2004-11-22 | Large Mass Scale by Strong Gauge Dynamics with Infrared Fixed Point | We consider a mechanism for realizing the desired decoupling of
strongly-coupled sector which is supposed to generate hierarchical structure of
the Yukawa couplings. In our mechanism, the same strongly-coupled sector is
responsible for generating a sufficiently flat potential and a large vacuum
expectation value (VEV) ... | 0411288v1 |
2005-02-17 | Small Yukawa Couplings from Type I String Theory and the Inflationary Solution to the Strong CP and $μ$ Problems | We investigate the origin of phenomenologically interesting small Yukawa
couplings in Type I string theory. Utilising the framework of intersecting sets
of D9 and orthogonal D5 branes we demonstrate the connection between extra
dimensional volumes and Yukawa couplings. For example, we show that extra
dimensions with in... | 0502156v1 |
2005-03-23 | Synthetic Running Coupling of QCD | Based on a study of the analytic running coupling obtained from the standard
perturbation theory results up to four-loop order, the QCD ``synthetic''
running coupling \alpha_{syn} is built. In so doing the perturbative time-like
discontinuity is preserved and nonperturbative contributions not only remove
the nonphysica... | 0503242v3 |
2005-07-04 | New physics in e+ e- -> Z gamma with polarized beams | We present a complete description of angular distributions in the presence of
new interactions for the process e+ e- -> Z gamma with polarized beams at
future linear colliders, by considering the most general form-factors allowed
by gauge invariance. We include the possibility of CP violation, and classify
the coupling... | 0507037v2 |
2005-08-09 | Radiative Electroweak Symmetry Breaking Beyond Leading Logarithms | The top-quark Yukawa coupling is too large to permit radiative electroweak
symmetry breaking to occur for small values of y, the Higgs self-coupling, to
leading-logarithm order. However, a large y solution leading to a viable Higgs
mass of approximately 220 GeV does exist, and differs from conventional
symmetry breakin... | 0508107v1 |
2005-08-11 | Effective-Lagrangian approach to gamma gamma --> WW; I: Couplings and amplitudes | We consider the gauge-boson sector of a locally SU(2) x U(1) invariant
effective Lagrangian with ten dimension-six operators added to the Lagrangian
of the Standard Model. These operators induce anomalous three- and
four-gauge-boson couplings and an anomalous gamma gamma H coupling. In the
framework of this effective L... | 0508132v2 |
2005-10-10 | The entropy of hot QCD at large N_f: Successfully testing weak coupling techniques | It has been known for some time that the entropy of hot QCD is well
reproduced by weak coupling techniques. These do not identify with perturbation
theory, known to have poor convergence properties, but involve resumming the
physics of hard thermal loops in the non-perturbative Phi-derivable two-loop
approximation. We ... | 0510115v1 |
2005-12-27 | Stable perturbative QCD predictions at moderate energies with a modified couplant | The problem of precise evaluation of perturbative QCD predictions at moderate
energies is addressed. In order to improve stability of the predictions with
respect to change of the renormalization scheme it is proposed to replace the
sequence of conventional renormalization group improved approximants by a
sequence of m... | 0512339v1 |
2006-02-16 | Disguising the Oblique Parameters | We point out a set of operator identities that relate the operators
corresponding to the oblique corrections to operators that modify fermion
couplings to the gauge bosons as well as operators that modify triple gauge
boson couplings. Such identities are simple consequences of the equations of
motion. Therefore the con... | 0602154v2 |
2006-03-17 | Evidence for infrared finite coupling in Sudakov resummation | New arguments are presented in favor of the infrared finite coupling approach
to power corrections in the context of Sudakov resummation. The more regular
infrared behavior of some peculiar combinations of Sudakov anomalous
dimensions, free of Landau singularities at large Nf, is pointed out. A general
conflict between... | 0603135v3 |
2006-04-13 | Tests of the naturalness of the coupling constants in ChPT at order p^6 | We derive constraints on combinations of O(p^6) chiral coupling constants by
matching a recent two-loop calculation of the pi-K scattering amplitude with a
set of sum rules. We examine the validity of the natural expectation that the
values of the chiral couplings can be associated with physics properties of the
light ... | 0604125v2 |
2006-04-13 | Lepton Flavor Violation in Intersecting D-brane Models | We investigate lepton flavor violation in the context of intersecting D-brane
models. We point out that these models have a source to generate flavor
violation in the trilinear scalar couplings while the geometry of the
construction leads to degenerate soft scalar masses for different generations
(as in the minimal sup... | 0604126v1 |
2006-04-26 | Constraints on flavor-changing Z' models by B_s mixing, Z' production, and B_s -> μ^+ μ^- | Certain string-inspired Z' models have non-universal interactions to three
families of fermions and induced tree-level flavor-changing couplings. We use
recent results on B_s-anti-B_s mixing to constrain the size of the
flavor-changing couplings in the b-s sector. In some highly predictive Z'
models, such a constraint ... | 0604223v1 |
2006-07-09 | U-boson detectability, and Light Dark Matter | The possible existence of a new gauge boson U, light and very weakly coupled,
allows for Light Dark Matter particles, which could also be at the origin of
the 511 keV line from the galactic bulge. Independently of dark matter, and
taking into account possible Z-U mixing effects, we show that, even under
favorable circu... | 0607094v1 |
2006-09-04 | Meson-octet-baryon couplings using light cone QCD sum rules | The coupling constants of K and pi mesons with the octet baryons are studied
in light cone QCD sum rules taking into account SU(3)f flavor symmetry breaking
effects, but keeping the SU(2) isospin symmetry intact. It is shown that, in
the SU(3)f flavor symmetry breaking case, all of the couplings can be written
in terms... | 0609026v2 |
2006-10-17 | Four-loop beta function and mass anomalous dimension in Dimensional Reduction | Within the framework of QCD we compute renormalization constants for the
strong coupling and the quark masses to four-loop order. We apply the DR-bar
scheme and put special emphasis on the additional couplings which have to be
taken into account. This concerns the epsilon-scalar--quark Yukawa coupling as
well as the ve... | 0610206v2 |
2006-11-01 | Self Interacting Dark Matter in the Solar System | Weakly coupled, almost massless, spin 0 particles have been predicted by many
extensions of the standard model of particle physics. Recently, the PVLAS group
observed a rotation of polarization of electromagnetic waves in vacuum in the
presence of transverse magnetic field. This phenomenon is best explained by the
exis... | 0611006v2 |
2006-11-14 | Gauge Coupling Unification in Six Dimensions | We compute the one-loop gauge couplings in six-dimensional non-Abelian gauge
theories on the T^2/Z_2 orbifold with general GUT breaking boundary conditions.
For concreteness, we apply the obtained general formulae to the gauge coupling
running in a 6D SO(10) orbifold GUT where the GUT group is broken down to the
standa... | 0611196v4 |
2006-12-15 | Radiative Yukawa Couplings for Supersymmetric Higgs Singlets at Large tan(beta) | Singlet Higgs bosons present in extensions of the MSSM can have sizable
Yukawa couplings to the b quark and the tau lepton for large values of
tan(beta) at the 1-loop level. We present an effective Lagrangian which
incorporates these tan(beta)-enhanced Yukawa couplings and which enables us to
study their effect on sing... | 0612188v2 |
2007-01-22 | Successful Yukawa structures in Warped Extra Dimensions | For a RS model, with SM fields in the bulk and the Higgs boson on the
TeV-brane, we suggest two specific structures for the Yukawa couplings, one
based on a permutation symmetry and the other on the Universal Strength of
Yukawa couplings hypothesis (USY). In USY, all Yukawa couplings have equal
strength and the differe... | 0701180v2 |
1992-07-22 | Quantum Kinks: Solitons at Strong Coupling | We examine solitons in theories with heavy fermions. These ``quantum''
solitons differ dramatically from semi-classical (perturbative) solitons
because fermion loop effects are important when the Yukawa coupling is strong.
We focus on kinks in a $(1+1)$--dimensional $\phi^4$ theory coupled to
fermions; a large-$N$ expa... | 9207074v1 |
1994-02-01 | Strong-Weak Coupling Duality in Four Dimensional String Theory | We present several pieces of evidence for strong-weak coupling duality
symmetry in the heterotic string theory, compactified on a six dimensional
torus. These include symmetry of the 1) low energy effective action, 2) allowed
spectrum of electric and magnetic charges in the theory, 3) allowed mass
spectrum of particles... | 9402002v2 |
1994-02-03 | A renormalization group approach to Hamiltonian light-front field theory | A perturbative renormalization group is formulated for the study of
Hamiltonian light-front field theory near a critical Gaussian fixed point. The
only light-front renormalization group transformations found that can be
approximated by dropping irrelevant operators and using perturbation theory
near Gaussian fixed volu... | 9402015v1 |
1994-02-14 | Scattering of Vortices at near-critical coupling | The scattering of vortices at a critical value of the coupling constant in
the Lagrangian can be approximated by a geodesic motion in the moduli space of
classical static configurations of vortices. In this paper we give a scheme for
generalising this idea to couplings that are near to the critical value. By
perturbing... | 9402075v2 |
1994-02-16 | Extreme Domain Wall--Black Hole Complementarity in N=1SUPERGRAVITY with a General Dilaton Coupling | We study supersymmetric (extreme) domain walls in four-dimensional (4d) N=1
supergravity theories with a general dilaton coupling $\alpha > 0$. Type I
walls, which are static, planar (say, in ($x,y$) plane) configurations,
interpolate between Minkowski space-time and a vacuum with a varying dilaton
field. We classify t... | 9402089v2 |
1994-03-21 | Fermions Coupled to a Conformal Boundary: A Generalization of the Monopole-Fermion System | We study a class of models in which $N$ flavors of massless fermions on the
half line are coupled by an arbitrary orthogonal matrix to $N$ rotors living on
the boundary. Integrating out the rotors, we find the exact partition function
and Green's functions. We demonstrate that the coupling matrix must satisfy a
certain... | 9403125v1 |
1994-10-19 | BRS symmetry for Yang-Mills theory with exact renormalization group | In the exact renormalization group (RG) flow in the infrared cutoff $\Lambda$
one needs boundary conditions. In a previous paper on $SU(2)$ Yang-Mills theory
we proposed to use the nine physical relevant couplings of the effective action
as boundary conditions at the physical point $\Lambda=0$ (these couplings are
defi... | 9410138v1 |
1994-12-02 | 2d Gravity Coupled to Topological Minimal Models | We discuss the properties of the large phase space of the genus-0 topological
minimal $A_{k + 1}$ model coupled to 2d topological gravity. The minimal action
is perturbed by adding all possible gravitational descendants with non-trivial
couplings which form the infinite-dimensional large phase space. Some general
ident... | 9412024v1 |
1995-12-14 | Supersymmetric Wilson Loops, Superstring-Like Observables, and the Natural Coupling of Superstrings to Supersymmetric Gauge Theories | We obtain an explicit expression for the supersymmetric Wilson loop in terms
of chiral superfields and supercurrents in superspace. The result turns out to
be different from what one would expect from the simple replacement of Lie
algebra valued connection in the exponent with the corresponding super-Lie
algebraic one.... | 9512098v1 |
1996-01-31 | Truly Strong Coupling and Large Radius in String Theory | String theory, if it describes nature, is probably strongly coupled. In light
of recent developments in string duality, this means that the ``real world''
should correspond to a region of the classical moduli space which admits no
weak coupling description. We exhibit, in the heterotic string, one such region
of the mo... | 9601175v3 |
1996-02-13 | Strong Coupling Expansion Of Calabi-Yau Compactification | In a certain strong coupling limit, compactification of the $E_8\times E_8$
heterotic string on a Calabi-Yau manifold $X$ can be described by an
eleven-dimensional theory compactified on $X\times \S^1/\Z_2$. In this limit,
the usual relations among low energy gauge couplings hold, but the usual
(problematic) prediction... | 9602070v2 |
1996-05-15 | Solving the strongly coupled 2D gravity III: String susceptibility and topological N-point functions | We spell out the derivation of novel features, put forward earlier in a
letter, of two dimensional gravity in the strong coupling regime, at $C_L=7$,
13, 19. Within the operator approach previously developed, they neatly follow
from the appearence of a new cosmological term/marginal operator, different
from the standar... | 9605105v1 |
1997-02-18 | Clifford Algebras in Finite Quantum Field Theories, I. Irreducible Yukawa Finiteness Condition | Finite quantum field theories may be constructed from the most general
renormalizable quantum field theory by forbidding, order by order in the
perturbative loop expansion, all ultraviolet-divergent renormalizations of the
physical parameters of the theory. The relevant finiteness conditions resulting
from this require... | 9702137v1 |
1997-05-26 | The Yukawa Coupling in Three Dimensions | We consider several renormalizable, scale free models in three space-time
dimensions which involve scalar and spinor fields. The Yukawa couplings are
bilinear in both the spinor and scalar fields and the potential is of sixth
order in the scalar field. In a model with a single scalar field and a complex
Fermion field i... | 9705198v1 |
1997-11-10 | Duality-Symmetric Eleven-Dimensional Supergravity and its Coupling to M-Branes | The standard eleven-dimensional supergravity action depends on a three-form
gauge field and does not allow direct coupling to five-branes. Using previously
developed methods, we construct a covariant eleven-dimensional supergravity
action depending on a three-form and six-form gauge field in a
duality-symmetric manner.... | 9711055v2 |
1997-11-27 | Gaugino Condensation in M-theory on S^1/Z_2 | In the low energy limit of for M-theory on S^1/Z_2, we calculate the gaugino
condensate potential in four dimensions using the background solutions due to
Horava. We show that this potential is free of delta-function singularities and
has the same form as the potential in the weakly coupled heterotic string. A
general ... | 9711197v1 |
1997-12-23 | Transmission of Supersymmetry Breaking from a 4-Dimensional Boundary | In the strong-coupling limit of the heterotic string theory constructed by
Horava and Witten, an 11-dimensional supergravity theory is coupled to matter
multiplets confined to 10-dimensional mirror planes. This structure suggests
that realistic unification models are obtained, after compactification of 6
dimensions, as... | 9712214v2 |
1998-04-01 | The Non-Abelian Coulomb Phase of the Gauged Vector Model at Large N | The renormalization group flows of the coupling constants for the gauged U(N)
vector model, with N_f massless fermions in the defining representation, are
studied in the large N limit, to all orders in the scalar coupling lambda,
leading order in 1/N, and lowest two orders in the gauge coupling g^2. It is
shown that th... | 9804008v2 |
1998-08-10 | Reduction of Dual Theories | In view of the presence of a superpotential, the dual of a gauge theory like
SQCD contains two coupling parameters. The method of the Reduction of Couplings
is used in order to express the parameter of the superpotential in terms of the
dual gauge coupling. In the conformal window and above it, a unique, isolated
solut... | 9808054v2 |
1999-01-04 | Strong coupling expansion and Seiberg-Witten-Whitham equations | We study the Seiberg-Witten-Whitham equations in the strong coupling regime
of the N=2 super Yang-Mills theory in the vicinity of the maximal
singularities. In the case of SU(2) the Seiberg-Witten-Whitham equations fix
completely the strong coupling expansion. For higher rank SU(N) they provide a
set of non-trivial con... | 9901006v2 |
1999-02-03 | On Mirror Symmetry in Three Dimensional Abelian Gauge Theories | We present an identity relating the partition function of N=4 supersymmetric
QED to that of its dual under mirror symmetry. The identity is a generalized
Fourier transform. Many known properties of abelian theories can be derived
from this formula, including the mirror transforms for more general gauge and
matter conte... | 9902033v2 |
1999-02-17 | On running couplings in gauge theories from type-IIB supergravity | We construct an explicit solution of type-IIB supergravity describing the
strong coupling regime of a non-supersymmetric gauge theory. The latter has a
running coupling with an ultraviolet stable fixed point corresponding to the
N=4 SU(N) super-Yang-Mills theory at large N. The running coupling has a power
law behaviou... | 9902125v3 |
1999-07-29 | The spectrum of coupled random matrices | The study of the spectrum of coupled random matrices has received rather
little attention. To the best of our knowledge, coupled random matrices have
been studied, to some extent, by Mehta. In this work, we explain how the
integrable technology can be brought to bear to gain insight into the nature of
the distribution ... | 9907213v2 |
1999-10-01 | Approximations for strongly-coupled supersymmetric quantum mechanics | We advocate a set of approximations for studying the finite temperature
behavior of strongly-coupled theories in 0+1 dimensions. The approximation
consists of expanding about a Gaussian action, with the width of the Gaussian
determined by a set of gap equations. The approximation can be applied to
supersymmetric system... | 9910001v2 |
1999-10-01 | Gauging Yang-Mills Symmetries In 1+1-Dimensional Spacetime | We present a systematic and 'from the ground up' analysis of the 'minimal
coupling' type of gauging of Yang-Mills symmetries in (2,2)-supersymmetric
1+1-dimensional spacetime. Unlike in the familiar 3+1-dimensional N=1
supersymmetric case, we find several distinct types of minimal coupling
symmetry gauging, and so seve... | 9910007v2 |
1999-11-30 | The Mass Spectrum of N=1 SYM(2+1) at Strong Coupling | We consider supersymmetric Yang-Mills theory on R x S^1 x S^1. In particular,
we choose one of the compact directions to be light-like and another to be
space-like. Since the SDLCQ regularization explicitly preserves supersymmetry,
this theory is totally finite, and thus we can solve for bound state wave
functions and ... | 9911243v1 |
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