2,121 research outputs found
Renormalizability of the massive Yang-Mills theory
It is shown that the massive Yang-Mills theory is on mass-shell
renormalizable. Thus the Standard Model of electroweak interactions can be
modified by removing terms with the scalar field from the Lagrangian in the
unitary gauge. The resulting electroweak theory without the Higgs particle is
on mass-shell renormalizable and unitary.Comment: 9 page
Calculating loops without loop calculations: NLO computation of pentaquark correlators
We compute next-to-leading order (NLO) perturbative QCD corrections to the
correlators of interpolating pentaquark currents. We employ modular techniques
in configuration space which saves us from the onus of having to do loop
calculations. The modular technique is explained in some detail. We present
explicit NLO results for several interpolating pentaquark currents that have
been written down in the literature. Our modular approach is easily adapted to
the case of NLO corrections to multiquark correlators with an arbitrary number
of quarks/antiquarks.Comment: 23 pages, 1 figure, published version. arXiv admin note: text overlap
with arXiv:hep-lat/031001
Relating Physical Observables in QCD without Scale-Scheme Ambiguity
We discuss the St\"uckelberg-Peterman extended renormalization group
equations in perturbative QCD, which express the invariance of physical
observables under renormalization-scale and scheme-parameter transformations.
We introduce a universal coupling function that covers all possible choices of
scale and scheme. Any perturbative series in QCD is shown to be equivalent to a
particular point in this function. This function can be computed from a set of
first-order differential equations involving the extended beta functions. We
propose the use of these evolution equations instead of perturbative series for
numerical evaluation of physical observables. This formalism is free of
scale-scheme ambiguity and allows a reliable error analysis of higher-order
corrections. It also provides a precise definition for as the pole in the associated 't Hooft scheme. A concrete application to
is presented.Comment: Plain TEX, 4 figures (available upon request), 22 pages,
DOE/ER/40322-17
Three loop MSbar renormalization of QED in the 't~Hooft-Veltman gauge
Quantum electrodynamics (QED) fixed in the 't~Hooft-Veltman gauge is
renormalized to three loops in the MSbar scheme. The beta-functions and
anomalous dimensions are computed as functions of the usual QED coupling and
the additional coupling, xi, which is introduced as part of the nonlinear gauge
fixing condition. Similar to the maximal abelian gauge of quantum
chromodynamics, the renormalization of the gauge parameter is singular.Comment: 8 latex page
Next-to-next-to-leading order fits to CCFR'97 data and infrared renormalons
We briefly summarize the outcomes of our recent improved fits to the
experimental data of CCFR collaboration for structure function of deep-inelastic scattering at the next-to-next-to-leading order. Special
attention is paid to the extraction of and the parameter of the
infrared renormalon model for -correction at different orders of
perturbation theory. The results can be of interest for planning similar
studies using possible future data of Neutrino Factories.Comment: 3 pages, presented at WG3 of 4th NuFact'02 Workshop, London 1-6 July,
200
A multiloop improvement of non-singlet QCD evolution equations
An approach is elaborated for calculation of "all loop" contributions to the
non-singlet evolution kernels from the diagrams with renormalon chain
insertions. Closed expressions are obtained for sums of contributions to
kernels for the DGLAP equation and for the "nonforward" ER-BL
equation from these diagrams that dominate for a large value of , the
first -function coefficient. Calculations are performed in the covariant
-gauge in a MS-like scheme. It is established that a special choice of the
gauge parameter generalizes the standard "naive nonabelianization"
approximation. The solutions are obtained to the ER-BL evolution equation
(taken at the "all loop" improved kernel), which are in form similar to
one-loop solutions. A consequence for QCD descriptions of hard processes and
the benefits and incompleteness of the approach are briefly discussed.Comment: 13 pages, revtex, 2 figures are enclosed as eps-file, the text style
and figures are corrected following version, accepted for publication to
Phys. Rev.
The dependence of the measured asymmetry : the test of the Bjorken sum rule
We analyse the proton and deutron data on spin dependent asymmetry
supposing the DIS structure functions and
have the similar -dependence. As a result, we have obtained
that at and
at , what is in the
best agreement with the Bjorken sum rule predictions.Comment: LaTeX, 5 pages, no figures, to be published in JETP Letter
Tau neutrino deep inelastic charged current interactions
The nu_mu -> nu_tau oscillation hypothesis will be tested through nu_tau
production of tau in underground neutrino telescopes as well as long-baseline
experiments. We provide the full QCD framework for the evaluation of tau
neutrino deep inelastic charged current (CC) cross sections, including
next-leading-order (NLO) corrections, charm production, tau threshold, and
target mass effects in the collinear approximation. We investigate the
violation of the Albright-Jarlskog relations for the structure functions F_4,5
which occur only in heavy lepton (tau) scattering. Integrated CC cross sections
are evaluated naively over the full phase space and with the inclusion of DIS
kinematic cuts. Uncertainties in our evaluation based on scale dependence, PDF
errors and the interplay between kinematic and dynamical power corrections are
discussed and/or quantified.Comment: 28 pages, 10 figure
- …