7,286 research outputs found
Some Simple (Integrable) Models of Fractional Statistics
In the first part, we introduce the notion of fractional statistics in the
sense of Haldane. We illustrate it on simple models related to anyon physics
and to integrable models solvable by the Bethe ansatz. In the second part, we
describe the properties of the long-range interacting spin chains. We describe
its infinite dimensional symmetry, and we explain how the fractional statistics
of its elementary excitations is an echo of this symmetry. In the third part,
we review recent results on the Yangian representation theory which emerged
from the study of the integrable long-range interacting models.Comment: 18 pages, Latex. Two lectures presented at 1994 Les Houches Summer
School ``Fluctuating Geometries in Statistical Mechanics and Field Theory''
(also available at http://xxx.lanl.gov/lh94/
Low-energy hadronic cross sections measurements at BABAR and g-2 of the muon
The LO hadronic vacuum polarization (VP) contribution to the muon anomalous
magnetic moment is obtained as the integral as a function of energy of
an expression that involves the ratio of the cross section to the pointlike muon pair cross section. The
former is extracted from experimental data for individual hadronic final states
at low energies, and from perturbative QCD at high energies. The BaBar
experiment at SLAC has a programme of systematic measurement of the production
of the lowest-rest-mass hadronic final states, those that contribute most
significantly to the integral. To that purpose, we use a method in which, while
the PEP-II storage ring is operated at a constant energy in the center of mass
system, , of about 10.6 GeV, events are reconstructed and selected
which have been produced with a hadronic final state together with a
high-energy photon which may (photon tagging) or may not (no tagging) be
observed. In our kinematic configuration the photon is almost always emitted by
the electron or by the positron of the initial state, hence the name
"initial-state radiation" (ISR). The cross section for the direct production of a final state at an energy is then
extracted from the differential cross section of the ISR production of the
state with invariant mass . The programme is almost completed
and has lead to a number of first measurements and to an improvement of up to a
factor of three of the uncertainties on the contributions of individual
channels to .Comment: On behalf of the BaBar Collaboration. Talk given at QCD 16, 19th
International Conference in Quantum Chromodynamics, 4 - 8 July 2016,
Montpellier, France. Proceedings submitted to Nuclear and Particle Physics
Proceeding
An Introduction to Yangian Symmetries
We review some aspects of the quantum Yangians as symmetry algebras of
two-dimensional quantum field theories. The plan of these notes is the
following: 1 - The classical Heisenberg model: Non-Abelian symmetries;
The generators of the symmetries and the semi-classical Yangians;
An alternative presentation of the semi-classical Yangians;
Digression on Poisson-Lie groups. 2 - The quantum Heisenberg chain:
Non-Abelian symmetries and the quantum Yangians;
The transfer matrix and an alternative presentation of the Yangians;
Digression on the double Yangians. Talk given at the "Integrable Quantum
Field Theories" conference held at Come, Italy , September 13-19, 1992.Comment: 14 pages, SPTh-92-134, (The Tex has been corrected
On The Three Point Velocity Correlation Functions in 2d Forced Turbulence
We present a simple exact formula for the three point velocity correlation
functions in two dimensional turbulence which is valid on all scales and which
interpolates between the direct and inverse cascade regimes. As expected, these
correlation functions are universal in these extreme regimes. We also discuss
the effect of anisotropy and friction.Comment: 6 pages, LateX, a small remark adde
Quantum Symmetries in 2D Massive Field Theories
We review various aspects of (infinite) quantum group symmetries in 2D
massive quantum field theories. We discuss how these symmetries can be used to
exactly solve the integrable models. A possible way for generalizing to three
dimensions is shortly described.Comment: 40 page
Results on conventional and exotic charmonium at BaBar
The B factories provide a unique playground for studying the properties of
conventional and exotic charmonium states. We present recent results in initial
state radiation and two-photon fusion, obtained using the full data set
collected by the BaBar experiment. Amongst BaBar 's harvest presented in this
talk, the determination of the quantum numbers of the X(3915) resonance, a body
of concording evidence pointing to JPC = 1++ for the X(3872), and updates on
the family of the Y resonance to the full integrated luminosity.Comment: Presented at DIS2013, the XXI International Workshop on
Deep-Inelastic Scattering and Related Subject -DIS2013, 22-26 April 2013
Marseille, France. To appear in Proceedings of Scienc
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