14 research outputs found
Probing CP Violation with the Deuteron Electric Dipole Moment
We present an analysis of the electric dipole moment (EDM) of the deuteron as
induced by CP-violating operators of dimension 4, 5 and 6 including theta QCD,
the EDMs and color EDMs of quarks, four-quark interactions and the Weinberg
operator. We demonstrate that the precision goal of the EDM Collaboration's
proposal to search for the deuteron EDM, (1-3)\times 10^{-27} e cm, will
provide an improvement in sensitivity to these sources of one-two orders of
magnitude relative to the existing bounds. We consider in detail the level to
which CP-odd phases can be probed within the MSSM.Comment: 5 pages, 4 figures; precision estimates clarified, to appear in Phys.
Rev.
Matching functions for heavy particles
We introduce matching functions as a means of summing heavy-quark logarithms
to any order. Our analysis is based on Witten's approach, where heavy quarks
are decoupled one at a time in a mass-independent renormalization scheme. The
outcome is a generalization of the matching conditions of Bernreuther and
Wetzel: we show how to derive closed formulas for summed logarithms to any
order, and present explicit expressions for leading order and next-to-leading
order contributions. The decoupling of heavy quarks in theories lacking
asymptotic freedom is also considered.Comment: Revised version to be published in Physical Review D; added section
with application to decoupling of heavy particles in non-asymptotically free
theorie
In search of the QCD-Gravity correspondence
Quantum Chromodynamics (QCD) is the fundamental theory of strong
interactions. It describes the behavior of quarks and gluons which are the
smallest known constituents of nuclear matter. The difficulties in solving the
theory at low energies in the strongly interacting, non-perturbative regime
have left unanswered many important questions in QCD, such as the nature of
confinement or the mechanism of hadronization. In these lectures oriented
towards the students we introduce two classes of dualities that attempt to
reproduce many of the features of QCD, while making the treatment at strong
coupling more tractable: (1) the AdS/CFT correspondence between a specific
class of string theories and a conformal field theory and (2) an effective
low-energy theory of QCD dual to classical QCD on a curved conformal
gravitational background. The hope is that by applying these dualities to the
evaluation of various properties of the strongly-interacting matter produced in
heavy ion collisions one can understand how QCD behaves at strong coupling. We
give an outline of the applications, with emphasis on two transport
coefficients of QCD matter -- shear and bulk viscosities.Comment: 31 pages, 7 figures; Lectures delivered by D. Kharzeev at the
International QGP Winter School, Jaipur, India, February 1-3, 200
Hadron Structure on the Lattice
A few chosen nucleon properties are described from a lattice QCD perspective:
the nucleon sigma term and the scalar strangeness in the nucleon; the vector
form factors in the nucleon, including the vector strangeness contribution, as
well as parity breaking effects like the anapole and electric dipole moment;
and finally the axial and tensor charges of the nucleon. The status of the
lattice calculations is presented and their potential impact on phenomenology
is discussed.Comment: 17 pages, 9 figures; proceedings of the Conclusive Symposium of the
Collaborative Research Center 443 "Many-body structure of strongly
interacting systems", Mainz, February 23-25, 201
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ
What Scattering Tells Us About Chiral Perturbation Theory
We describe a rearrangement of the standard expansion of the symmetry
breaking part of the QCD effective Lagrangian that includes into each order
additional terms which in the standard chiral perturbation theory (PT)
are relegated to higher orders. The new expansion represents a systematic and
unambiguous generalization of the standard PT, and is more likely to
converge rapidly. It provides a consistent framework for a measurement of the
importance of additional ``higher order'' terms whose smallness is usually
assumed but has never been checked. A method of measuring, among other
quantities, the QCD parameters and the quark
mass ratio is elaborated in detail. The method is illustrated
using various sets of available data. Both of these parameters might be
considerably smaller than their respective leading order standard PT
values. The importance of new, more accurate, experimental information on
low-energy scattering is stressed.Comment: RevTeX 62 pages (6 figures not added, request from any author),
IPNO/TH 92-106, PURD-TH-93-0
Wool Insectproofing with Surface-Active Agents Part I. Anionics and Anionic-Cationic Complexes
The reactions Ï Ï â Ï Ï and Îł Îł â Ï Ï in Ï PT with an isosinglet scalar resonance
The lowest-lying resonance in the QCD spectrum is the isoscalar
meson, also known as the . We augment SU(2) chiral
perturbation theory (PT) by including the meson as an additional
explicit degree of freedom, as proposed by Soto, Talavera, and Tarr\'us and
others. In this effective field theory, denoted PT, the
meson's well-established mass and decay width are not sufficient to properly
renormalize its self energy. At another low-energy constant
appears in the dressed -meson propagator; we adjust it so that the
isoscalar pion-pion scattering length is also reproduced. We compare the
resulting amplitudes for the and
reactions to data from threshold through the
energies at which the -meson resonance affects observables. The
leading-order (LO) amplitude reproduces the -meson pole
position, the isoscalar scattering lengths and scattering
and data up to GeV.
It also yields a amplitude that obeys the Ward
identity. The value obtained for the polarizability is, however, only
slightly larger than that obtained in standard PT.Comment: 17 pages, 7 figures. This version, which will be published in
European Physical Journal A, contains clarification and more explanation of
several points, as well as additional reference
The U(1)A Anomaly and QCD Phenomenology
The role of the U(1)A anomaly in QCD phenomenology is reviewed, focus- ing on the relation between quark dynamics and gluon topology. Topics covered include a generalisation of the Witten-Veneziano formula for the mass of the ηâČ, the determina- tion of pseudoscalar meson decay constants, radiative pseudoscalar decays and the U(1)A Goldberger-Treiman relation. Sum rules are derived for the proton and photon structure functions g1p and g1Îł measured in polarised deep-inelastic scattering. The first moment sum rule for g1p (the âproton spinâ problem) is confronted with new data from COMPASS and HERMES on the deuteron structure function and shown to be quantitatively explained in terms of topological charge screening. Proposals for experiments on semi-inclusive DIS and polarised two-photon physics at future ep and high-luminosity e+eâ colliders are discussed