Search results for "Coupled"

Viability of Strongly Coupled Scenarios with a Light Higgs-like Boson

2013

We present a one-loop calculation of the oblique S and T parameters within strongly coupled models of electroweak symmetry breaking with a light Higgs-like boson. We use a general effective Lagrangian, implementing the chiral symmetry breaking SU(2)(L) circle times SU(2)(R) -> SU(2)(L+R) with Goldstone bosons, gauge bosons, the Higgs-like scalar, and one multiplet of vector and axial-vector massive resonance states. Using a dispersive representation and imposing a proper ultraviolet behavior, we obtain S and T at the next-to-leading order in terms of a few resonance parameters. The experimentally allowed range forces the vector and axial-vector states to be heavy, with masses above the TeV …

Viability of light-Higgs strongly-coupled scenarios

2013

Contrary to what is sometimes stated, the current electroweak precision data easily allow for massive composite resonance states at the natural EW scale, i.e., well over the TeV. The oblique parameters S and T are analyzed by means of an effective Lagrangian that implements the $SU(2)_L\otimes SU(2)_R\to SU(2)_{L+R}$ pattern of electroweak symmetry breaking. They are computed at the one-loop level and incorporating the newly discovered Higgs-like boson and possible spin-1 composite resonances. Imposing a proper ultraviolet behaviour is crucial and allows us to determine S and T at next-to-leading order in terms of a few resonance parameters. Electroweak precision data force the vector and a…

Magnetic properties of smooth terminating dipole bands in 110,112Te

2006

Three strongly coupled sequences have been established in Te-110,Te-112 up to high spins. They are interpreted in terms of deformed structures built on proton 1-particle-1-hole excitations that reach termination at I similar to 40h. This is the first observation of smooth terminating dipole structures in this mass region. Lifetime measurements have allowed the extraction of experimental B(M 1; 1 -> I - 1) and B(E2; I -> I - 2) reduced transition rates for one of the dipole bands in Te-110. The results support the deformed interpretation. (c) 2006 Elsevier B.V. All rights reserved.

γ-ray and decay spectroscopy of194,195,196At

2013

Excited states of ${}^{195}$At have been studied by means of in-beam $\ensuremath{\gamma}$-ray spectroscopy and the recoil-decay tagging technique. A strongly coupled rotational band feeding the $\ensuremath{\alpha}$-decaying $7/{2}^{\ensuremath{-}}$ state via unobserved transitions was identified. This band is presumably built on the oblate proton ${I}^{\ensuremath{\pi}}=13/{2}^{+}$ state. Confirming earlier measurements, $\ensuremath{\alpha}$ decays from the $1/{2}^{+}$ and $7/{2}^{\ensuremath{-}}$ states were observed. Additionally, an $E3$ branch competing with the $\ensuremath{\alpha}$ decay of the $7/{2}^{\ensuremath{-}}$ state was inferred. Also $\ensuremath{\alpha}$ decays of the od…

Strongly coupled bands in the neutron-deficient nucleus167Re

2003

Excited states in the neutron-deficient nucleus Re-167 have been observed in a recoil-tagging experiment performed with the Jurosphere gamma-ray spectrometer in conjunction with the RITU gas-filled ...

Structure of rotational bands in 253No

2009

In-beam gamma-ray and conversion electron spectroscopic studies have been performed on the 253 No nucleus. A strongly coupled rotational band has been identified and the improved statistics allows an assignment of the band structure as built on the $\ensuremath 9/2^-[734]_{\nu}$ ground state. The results agree with previously known transition energies but disagree with the tentative structural assignments made in earlier work.

Rotational features of vibrator nucleus118Te

1999

High-spin states in ${}^{118}\mathrm{Te}$ have been populated via heavy-ion induced reactions. Excited states were observed up to $I=32\ensuremath{\Elzxh}$ and, in addition to irregular level sequences, several bands were identified for the first time. The decoupled negative parity bands based upon ${7}^{\ensuremath{-}}$ and ${8}^{\ensuremath{-}}$ states are interpreted to arise from the proton ${h}_{11/2}{g}_{7/2}$ configuration coupled to the $2p\ensuremath{-}2h$ intruder states in ${}^{116}\mathrm{Sn}.$ These bands show very smooth alignment behavior, in accordance with the proton ${h}_{11/2}$ bands in neighboring Sb and I nuclei. Above $I=20$ the yrast positive parity band is built on t…

Coulomb sum rule for He4 and O16 from coupled-cluster theory

2020

We demonstrate the capability of coupled-cluster theory to compute the Coulomb sum rule for the $^{4}\mathrm{He}$ and $^{16}\mathrm{O}$ nuclei using interactions from chiral effective field theory. We perform several checks, including a few-body benchmark for $^{4}\mathrm{He}$. We provide an analysis of the center-of-mass contaminations, which we are able to safely remove. We then compare with other theoretical results and experimental data available in the literature, obtaining a fair agreement. This is a first and necessary step towards initiating a program for computing neutrino-nucleus interactions from first principles in coupled-cluster theory and supporting the experimental long-base…

Coupled-cluster Theory

2002

New Insight into the Cluster Structure of $^9$Be by Reactions with Deuteron Beam

2018

International audience; Angular distributions of protons, deuterons, tritons, and alpha particles emitted in the reaction 2H+9Be at Elab=19.5, 25, and 35 MeV were measured to study the structure of 9Be, especially to shed light on the internal clusters and possible cluster transfer of 5He. The experiments were performed at sufficiently high energies to ensure suppression of compound nucleus contribution. Thus, the direct reaction mechanism should be mainly responsible for the measured five-nucleon transfer cross section. The analysis suggests a significant contribution of simultaneous five-nucleon transfer in the reaction channel 9Be (d,4He) 7Li.