278 research outputs found
On Factorization of Generalized Macdonald Polynomials
A remarkable feature of Schur functions -- the common eigenfunctions of
cut-and-join operators from -- is that they factorize at the
peculiar two-parametric topological locus in the space of time-variables, what
is known as the hook formula for quantum dimensions of representations of
and plays a big role in various applications. This factorization
survives at the level of Macdonald polynomials. We look for its further
generalization to {\it generalized} Macdonald polynomials (GMP), associated in
the same way with the toroidal Ding-Iohara-Miki algebras, which play the
central role in modern studies in Seiberg-Witten-Nekrasov theory. In the
simplest case of the first-coproduct eigenfunctions, where GMP depend on just
two sets of time-variables, we discover a weak factorization -- on a
codimension-one slice of the topological locus, what is already a very
non-trivial property, calling for proof and better understanding.Comment: 8 page
The 2-leg vertex in K-theoretic DT theory
K-theoretic Donaldson-Thomas counts of curves in toric and many related
threefolds can be computed in terms of a certain canonical 3-valent tensor, the
K-theoretic equivariant vertex. In this paper we derive a formula for the
vertex in the case when two out of three entries are nontrivial. We also
discuss some applications of this result.Comment: 27 page
Measurement of decay rate and parameters at KEDR
Using the inclusive photon spectrum based on a data sample collected at the
peak with the KEDR detector at the VEPP-4M collider, we
measured the rate of the radiative decay as well
as mass and width. Taking into account an asymmetric photon
lineshape we obtained keV, MeV/, MeV.Comment: 6 pages, 3 figure
Measurement of B(J/psi->eta_c gamma) at KEDR
We present a study of the inclusive photon spectrum from 6.3 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of the radiative decay J/psi -> eta_c gamma,
eta_c width and mass. Taking into account an asymmetric photon line shape we
obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4
+- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th
International Workshop on Charm Physics (Charm2010), October 21-24, 2010,
IHEP, Beijin
Precise measurement of and between 1.84 and 3.72 GeV at the KEDR detector
The present work continues a series of the KEDR measurements of the value
that started in 2010 at the VEPP-4M collider. By combining new data
with our previous results in this energy range we measured the values of
and at nine center-of-mass energies between 3.08 and 3.72
GeV. The total accuracy is about or better than at most of energy
points with a systematic uncertainty of about . Together with the
previous precise measurement at KEDR in the energy range 1.84-3.05 GeV, it
constitutes the most detailed high-precision measurement near the
charmonium production threshold.Comment: arXiv admin note: text overlap with arXiv:1610.02827 and substantial
text overlap with arXiv:1510.0266
Measurement of J/psi to eta_c gamma at KEDR
We present a study of the inclusive photon spectra from 5.9 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c
width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV,
G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009,
Beijing, Chin
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