Search results for "Tensor"
showing 10 items of 550 documents
Discriminating between technicolor and warped extra dimensional model viapp→ZZchannel
2009
We explore the possibility to discriminate between certain strongly coupled technicolor (TC) models and warped extra dimensional models where the standard model fields are propagating in the extra dimension. We consider a generic QCD-like TC model with running coupling as well as two TC models with walking dynamics. We argue that, due to the different production mechanisms for the lowest-lying composite tensor state in these TC theories compared to the first Kaluza-Klein graviton mode of the warped extra dimensional case, it is possible to distinguish between these models based on the angular analysis of the reconstructed longitudinal $Z$ bosons in the $pp\ensuremath{\rightarrow}ZZ\ensurema…
Chiral Perturbation Theory with tensor sources
2007
23 pages, 1 figure.-- ISI Article Identifier: 000249788800051.-- ArXiv pre-print available at: http://arxiv.org/abs/0705.2948
Improved bounds on SUSY accompanied neutrinoless double beta decay
1998
Neutrinoless double beta decay induced by light Majorana neutrino exchange between two decaying nucleons with squark/slepton exchange inside one and W exchange inside the other nucleon (so-called vector-scalar exchange) gives stringent limits on R-parity violating interactions. We have extended previous work by including the tensor contribution to the transition rate. We discuss the improved limits on trilinear \Rp -MSSM couplings imposed by the current experimental limit on the $\znbb$ decay half-life of $^{76}$Ge.
Decay of axial-vector mesons into VP andPγ
2004
We propose a phenomenological Lagrangian for the decay of the SU(3) nonets of the axial-vector mesons of J{sup PC}=1{sup +-},1{sup ++} into a vector meson and a pseudoscalar constructed with tensor fields for the vector and axial-vector mesons. The formulation leads to a good reproduction of the different decay branching ratios and assuming vector meson dominance (VMD) it also leads to good results for the radiative decay of the a{sub 1} into pion and photon, and in agreement with the structure proposed in the chiral tensor formulation of radiative decay of axial-vector mesons. The two SU(3) parameters and the mixing angle of K{sub 1A} and K{sub 1B} needed to give the physical K{sub 1}(1270…
Single-spin asymmetries of $d(\gamma,\pi)NN$ in the first resonance region
2003
Incoherent photoproduction of pions on the deuteron in the first resonance region is investigated with special emphasis on single-spin asymmetries. For the elementary pion production operator an effective Lagrangian model which includes the standard pseudovector Born terms and a resonance contribution from the $\Delta$(1232)-excitation is used. Single-spin asymmetries, both for charged and neutral pion photoproduction on the deuteron, are analyzed and calculated for the first time in the first resonance region. The linear photon asymmetry $\Sigma$, vector target asymmetry $T_{11}$ and tensor target asymmetries $T_{20}$, $T_{21}$, and $T_{22}$ for the reaction $d(\gamma,\pi)NN$ are predicted…
Cross section ratio and angular distributions of the reaction p + d -> 3He + eta at 48.8 MeV and 59.8 MeV excess energy
2014
We present new data for angular distributions and on the cross section ratio of the p + d -> 3He + eta reaction at excess energies of Q = 48.8 MeV and Q = 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum J\"ulich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20 MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval.
Shell structure beyond the proton drip line studied via proton emission from deformed 141Ho
2008
Abstract Fine structure in proton emission from the 7 / 2 − [ 523 ] ground state and from the 1 / 2 + [ 411 ] isomer in deformed nucleus 141Ho was studied by means of fusion-evaporation reactions and digital signal processing. Proton transitions to the first excited 2+ state in 140Dy, with the branching ratio of I p g s ( 2 + ) = 0.9 ± 0.2 % and I p m ( 2 + ) = 1.7 ± 0.5 % , were observed. The data are analyzed within the non-adiabatic weak coupling model assuming a large quadrupole deformation of the daughter nucleus 140Dy as predicted by the self-consistent theory. Implications of this result on coexistence effects around N = 74 are discussed. Significant modifications of the proton shell…
Factorization in closed string field theory
1994
Abstract The so long made assumption, that a general closed-string vertex operator V should be built as a product of left- and right-moving vertex operators, rests on the fact that the closed-string Fock spce is constructed as a tensor product of left- and right-moving open-string Fock spaces. In this letter we will relax this assumption by proving that factorization of closed-string vertices is a general rule.
Anomalous chiral perturbation theory meson Lagrangian to orderp6reexamined
2002
We present a revised and extended construction of the mesonic Lagrangian density in chiral perturbation theory (ChPT) at order ${p}^{6}$ in the anomalous (or epsilon) sector, ${\mathcal{L}}_{6,\ensuremath{\epsilon}}.$ After improving several aspects of the strategy we used originally, i.e., a more efficient application of partial integration, the implementation of so-called Bianchi identities, and additional trace relations, we find the new monomial sets to include 24 ${SU(N}_{f}),$ 23 $\mathrm{SU}(3),$ and 5 $\mathrm{SU}(2)$ elements. Furthermore, we introduce 8 supplementary terms due to the extension of the chiral group to ${SU(N}_{f}{)}_{L}\ifmmode\times\else\texttimes\fi{}{SU(N}_{f}{)}…
Cosmic Microwave Background anisotropies from second order gravitational perturbations
1997
This paper presents a complete analysis of the effects of second order gravitational perturbations on Cosmic Microwave Background anisotropies, taking explicitly into account scalar, vector and tensor modes. We also consider the second order perturbations of the metric itself obtaining them, for a universe dominated by a collision-less fluid, in the Poisson gauge, by transforming the known results in the synchronous gauge. We discuss the resulting second order anisotropies in the Poisson gauge, and analyse the possible relevance of the different terms. We expect that, in the simplest scenarios for structure formation, the main effect comes from the gravitational lensing by scalar perturbati…