18018794
Next-to-leading order calculation of a fragmentation function in a light-cone gauge
The short-distance coefficients for the color-octet {sup 3}S{sub 1} term in the fragmentation function for a gluon to split into polarized heavy quarkonium states are recalculated to order {alpha}{sub s}{sup 2}. The light-cone gauge remarkably simplifies the calculation by eliminating many Feynman diagrams at the expense of introducing spurious poles in loop integrals. We do not use any conventional prescriptions for spurious pole. Instead, we only use gauge invariance with the aid of Collins-Soper definition of the fragmentation function. Our result agrees with a previous calculation of Braaten and Lee in the Feynman gauge, but disagrees with another previous calculation.
124343131
Exclusive spin-2 glueball production associated with J/ψ from e +e- annihilation
118538298
Exclusive heavy quarkonium + γ production from e+e-annihilation into a virtual photon
We compute the cross section for exclusive production of a photon associated with a heavy quarkonium H of charge-conjugation parity C=+1 from e{sup +}e{sup -} annihilation into a virtual photon at the center-of-momentum energy {radical}(s)=10.58 GeV. The nonrelativistic QCD factorization formulas for the differential and total cross sections are obtained at leading order in the strong coupling and in the relative velocity of the heavy quark in the quarkonium rest frame. The predicted cross sections for the S-wave spin-singlet cases are about 80 fb and 50 fb for H={eta}{sub c} and {eta}{sub c}(2S), respectively. Among P-wave spin-triplet charmonia, {chi}{sub c1} has a particularly large cross section of about 14 fb. The cross sections for bottomonium states {eta}{sub b} and {chi}{sub bJ} are about 3 fb. A rough estimate of the background reveals that the signal significances for charmonium processes are sufficiently large enough to be detected with ease with the integrated luminosities available at the present B factories.
17297484
Color-octet mechanism in the inclusive D-wave charmonium productions in B decays
The inclusive D-wave charmonium production rates in B decays are considered in the Bodwin-Braaten-Lepage (BBL) approach. We find that the color-octet subprocesses B → cc(3S1(8) or 3PJ(80) + s, d, followed by the transition cc(3S1(8), or 3PJ(8)) → 3DJ, strongly dominate over any other subprocess, due to the large Wilson coefficient for the ΔB = 1 effective lagrangian. Assuming that the numerical values of the matrix elements 〈0|O3DJ(3S1(8))|0〉 and 〈0|O3DJ(3PJ(8))|0〉 are the same order of magnitudes with the 〈0|Oψ′ (3S1(8))|0〉, we find that the 1,3D2 can be observed B-factories.
116621787
Polarization of prompt J/ in proton-proton collisions at RHIC
Within the framework of the nonrelativistic QCD (NRQCD) factorization approach, we compute the polarization of prompt J/{psi} produced at the Brookhaven's Relativistic Heavy-Ion Collider from proton-proton collisions at the center-of-momentum energy {radical}(s)=200 GeV. The perturbative contributions are computed at leading order in the strong coupling constant. The prediction reveals that the color-singlet contribution severely underestimates the PHENIX preliminary data for the differential cross section integrated over the rapidity range |y|<0.35 and its contribution is strongly transversely polarized, which disagrees with the PHENIX preliminary data. After including the color-octet contributions, we find that the NRQCD predictions for both the cross section and polarization over the transverse-momentum range 1.5 GeV<p{sub T}<5 GeV (1.5 GeV<p{sub T}<2 GeV) integrated over the rapidity range |y|<0.35 (1.2<|y|<2.2) agree with the data within errors.
26919092
A Measurement of the Michel Parameters in Leptonic Decays of the Tau
We have measured the spectral shape Michel parameters {rho} and {eta} using leptonic decays of the {tau}, recorded by the CLEO II detector. Assuming e-{mu} universality, we find {rho}{sub e{mu}}= 0.735 {+-} 0.013 {+-} 0.008 and {eta}{sub e{mu}} = 0.015 {+-} 0.061 {+-} 0.062, where the first error is statistical and the second systematic.
15708185
COMPOSITE OPERATORS AND TOPOLOGICAL CONTRIBUTIONS IN GAUGE THEORY
In D-dimensional gauge theory with a kinetic term based on p-form tensor gauge field, we introduce a gauge-invariant operator associated with the composite form from an electric (p - 1)-brane and a magnetic (q - 1)-brane in D = p + q + 1 space–time dimensions. By evaluating the partition function of this operator, we show that the expectation value of this operator gives rise to the topological contributions identical to those in gauge theory with a topological Chern–Simons BF term.
119190735
Large-N c Gauge Theory and Chiral Random Matrix Theory
We discuss how the $1/N_c$ expansion and the chiral random matrix theory ($\chi$RMT) can be used in the study of large-$N_c$ gauge theories. We first clarify the parameter region in which each of these two approaches is valid: while the fermion mass $m$ is fixed in the standard large-$N_c$ arguments ('t Hooft large-$N_c$ limit), $m$ must be scaled appropriately with a certain negative power of $N_c$ in order for the gauge theories to be described by the $\chi$RMT. Then, although these two limits are not compatible in general, we show that the breakdown of chiral symmetry can be detected by combining the large-$N_c$ argument and the $\chi$RMT with some cares. As a concrete example, we numerically study the four dimensional $SU(N_c)$ gauge theory with $N_f=2$ heavy adjoint fermions, introduced as the center symmetry preserver keeping the infrared physics intact, on a $2^4$ lattice. By looking at the low-lying eigenvalues of the Dirac operator for a massless probe fermion in the adjoint representation, we find that the chiral symmetry is indeed broken with the expected breaking pattern. This result reproduces a well-known fact that the chiral symmetry is spontaneously broken in the pure $SU(N_c)$ gauge theory in the large-$N_c$ and the large-volume limit, and therefore supports the validity of the combined approach. We also provide the interpretation of the gap and unexpected $N_c$-scaling, both of which are observed in the Dirac spectrum.
119852910
Measurement of the mass difference between top and anti-top quarks in pp collisions at √s = 7 TeV using the ATLAS detector
A measurement of the mass difference between top and anti-top quarks is presented. In a 4.7 fb(-1) data sample of proton-proton collisions at root s = 7 TeV recorded with the ATLAS detector at the ...
118610109
The Sub-Saturn Mass Transiting Planet HAT-P-12b
We present new photometric data of the transiting planet HAT-P-12b observed in 2011. Our three transit curves are modeled using the JKTEBOP code and adopting the quadratic limb-darkening law. Including our measurements, 18 transit times spanning about 4.2 yr were used to determine the improved ephemeris with a transit epoch of 2,454,187.85560 ± 0.00011 BJD and an orbital period of 3.21305961 ± 0.00000035 days. The physical properties of the star-planet system are computed using empirical calibrations from eclipsing binary stars and stellar evolutionary models, combined with both our transit parameters and previously known spectroscopic results. We found that the absolute dimensions of the host star are M A = 0.73 ± 0.02 M ☉, R A = 0.70 ± 0.01 R ☉, log g A = 4.61 ± 0.02, ρA = 2.10 ± 0.09 ρ☉, and L A = 0.21 ± 0.01 L ☉. The planetary companion has M b = 0.21 ± 0.01 M Jup, R b = 0.94 ± 0.01 R Jup, log g b = 2.77 ± 0.02, ρb = 0.24 ± 0.01 ρJup, and T eq = 960 ± 14 K. Our results agree well with standard models of irradiated gas giants with a core mass of 11.3 M ⊕.
54190218
The N=8$$ \mathcal{N}=8 $$ superconformal bootstrap in three dimensions
A bstractWe analyze the constraints imposed by unitarity and crossing symmetry on the four-point function of the stress-tensor multiplet of N=8$$ \mathcal{N}=8 $$ superconformal field theories in three dimensions. We first derive the superconformal blocks by analyzing the superconformal Ward identity. Our results imply that the OPE of the primary operator of the stress-tensor multiplet with itself must have parity symmetry. We then analyze the relations between the crossing equations, and we find that these equations are mostly redundant. We implement the independent crossing constraints numerically and find bounds on OPE coefficients and operator dimensions as a function of the stress-tensor central charge. To make contact with known N=8$$ \mathcal{N}=8 $$ superconformal field theories, we compute this central charge in a few particular cases using supersymmetric localization. For limiting values of the central charge, our numerical bounds are nearly saturated by the large N limit of ABJM theory and also by the free U(1) × U(1) ABJM theory.