Search results for "Matrix"
showing 10 items of 3205 documents
On the description of non-unitary neutrino mixing
2015
28 pages.- 8 figures.- typos corrected.- modified bounds on non-unitarity parameters.- new figs 3 and 4
Searching for exotic states in the N pi K system
2009
We study the N pi K system in order to investigate the possibility of existence of strangeness +1 resonance(s). The formalism consists of solving the Faddeev equations with the N pi, pi K and KN t-matrices obtained from chiral dynamics. The same formalism, which leads to the finding of several 1/2(+) resonances in the corresponding three-body S = -1 channels in the 1400-2000 MeV energy region, results into only one broad bump around 1700 MeV with isospin 0. The amplitudes in isospin 1 and 2 configuration do not have any resonant structure. (C) 2009 Published by Elsevier B.V.
Measurement of the t-channel single top-quark production cross section in pp collisions at s=7 TeV with the ATLAS detector
2012
We report a measurement of the cross section of single top-quark production in the t-channel using 1.04 fb -1 of pp collision data at s=7 TeV recorded with the ATLAS detector at the LHC. Selected e ...
Evidence for s-channel single top quark production in pp¯ collisions at s=1.96 TeV
2013
We present measurements of the cross sections for the two main production modes of single top quarks in p (p) over bar collisions at root s = 1.96 TeV in the Run II data collected with the DO detector at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.7 fb(-1). The s-channel cross section is measured to be sigma(p (p) over bar -> tb + X) = 1.10(-0.31)(+0.33) pb with no assumptions on the value of the t-channel cross section. Similarly, the t-channel cross section is measured to be sigma(p (p) over bar -> tqb + X) = 3.07(-0.49)(+0.54) pb. We also measure the s + t combined cross section as sigma(p (p) over bar -> tb + X, tqb + X) = 4.11(-0.55)(+0.60) ph and set…
A SIMULTANEOUS ANALYSIS FOR THE ΔI = 1/2 RULE, DIRECT CP VIOLATION, $K^0 -\bar K^0$ AND $B^0 -\bar B^0$ MIXINGS
1992
To have a consistent picture, a simultaneous analysis for the K → ππ isospin amplitudes A0 and A2, the ΔI = 1/2 rule, CP-violating ε′/ε, and [Formula: see text] and [Formula: see text] mixings within the standard model is made by employing the recent reanalyzed values of the parameters and relating the penguin matrix elements involved in the K → ππ decays to the known matrix elements of the ΔI = 1/2 operator (Q2 − Q1) and ΔI = 3/2 operator (Q2 + 2Q1). The allowed values for all the relevant quantities are calculated in detail. A general bound for top quark mass mt, CP phase δ and ε′/ε is found: for δ in the second quadrant, 84 GeV ≤ mt ≤ 250 GeV , δ ≤ 173° and 1 × 10−4 < ε′/ε ≤ 1 × 10−2…
Non-standard neutrino oscillations: perspective from unitarity triangles
2021
We formulate an alternative approach based on unitarity triangles to describe neutrino oscillations in presence of non-standard interactions (NSI). Using perturbation theory, we derive the expression for the oscillation probability in case of NSI and cast it in terms of the three independent parameters of the leptonic unitarity triangle (LUT). The form invariance of the probability expression (even in presence of new physics scenario as long as the mixing matrix is unitary) facilitates a neat geometric view of neutrino oscillations in terms of LUT. We examine the regime of validity of perturbative expansions in the NSI case and make comparisons with approximate expressions existing in liter…
New determination of double-β-decay properties in48Ca: High-precisionQββ-value measurement and improved nuclear matrix element calculations
2014
We report a direct measurement of the Q-value of the neutrinoless double-beta-decay candidate 48Ca at the TITAN Penning-trap mass spectrometer, with the result that Q = 4267.98(32) keV. We measured the masses of both the mother and daughter nuclides, and in the latter case found a 1 keV deviation from the literature value. In addition to the Q-value, we also present results of a new calculation of the neutrinoless double-beta-decay nuclear matrix element of 48Ca. Using diagrammatic many-body perturbation theory to second order to account for physics outside the valence space, we constructed an effective shell-model double-beta-decay operator, which increased the nuclear matrix element by ab…
Universal features of the nuclear matrix elements governing the mass sector of the 0νββ decay
2005
In this work we report on manifest universal features found in the nuclear matrix elements which govern the mass sector of the neutrinoless double beta decay. The results are based on the analysis of the calculated matrix elements corresponding to the decays of 76Ge, 82Se, 100Mo, and 116Cd. The results suggest a dominance of few low-lying nuclear states of few multipoles in these matrix elements. Dedicated charge-exchange reactions could be used to probe these key states to determine experimentally the value of the nuclear matrix element.
Properties of the 12C 10 MeV state determined through β-decay
2005
16 pages, 1 table, 10 figures.-- PACS nrs.: 23.40.-s; 26.20.+f; 27.20.+n.-- Printed version published Oct 3, 2005.
Invarianzgruppen von Bewegungsgleichungen mit Kommutatorring
1967
An attempt to describe particles by hermitian operators obeying commutator relations leads to a ring of sixteen elements to be represented by matrices of infinite rank. Equations of motion containing elements of the ring are shown to be invariant under charge-conjugation, time-reversal and inhomogeneous Lorentz transformations. Analogs to Pauli- and Gursey-transformations can also be defined and may be used to introduce isospin and helicity.