152 research outputs found
Parity violation correlations in light muonic atoms
The 2 S -1 S transition in light muonic atoms is very sensitive to parity violation correlations induced via neutral currents. Observables depending on these transitions such as the photon polarization and the angular correlation between the emitted radiation and the atom polarization are a clear signal of weak neutral currents in atoms. We find the relation between the lepton and quark couplings and these observables emphasizing the effect of the nuclear spin. The results expected in muonic, atoms μ- 4 He and μ- 3 He are given.This work has been supported in part by
CICYT, under grant AE-0021. Two of us (J.B. and J.V.) are indebted to Ministerio de Educación y Ciencia and to C.S.I.C., respectively for the research fellowships.Peer reviewe
Witten's cubic vertex in the comma theory (I)
It is shown that Witten's interaction 3-vertex is a solution to the comma overlap equations; hence establishing the equivalence between the conventional and the 'comma' formulation of interacting string theory at the level of vertices
On the Corner Elements of the CKM and PMNS Matrices
Recent experiments show that the top-right corner element () of the
PMNS, like that () of the CKM, matrix is small but nonzero, and suggest
further via unitarity that it is smaller than the bottom-left corner element
(), again as in the CKM case (). An attempt in
explaining these facts would seem an excellent test for any model of the mixing
phenomenon. Here, it is shown that if to the assumption of a universal rank-one
mass matrix, long favoured by phenomenologists, one adds that this matrix
rotates with scale, then it follows that (A) by inputting the mass ratios
, and , (i) the corner elements are
small but nonzero, (ii) , , (iii)
estimates result for the ratios and , and
(B) by inputting further the experimental values of and
, (iv) estimates result for the values of the corner elements
themselves. All the inequalities and estimates obtained are consistent with
present data to within expectation for the approximations made.Comment: 9 pages, 2 figures, updated with new experimental data and more
detail
A Solution of the Strong CP Problem Transforming the theta-angle to the KM CP-violating Phase
It is shown that in the scheme with a rotating fermion mass matrix (i.e. one
with a scale-dependent orientation in generation space) suggested earlier for
explaining fermion mixing and mass hierarchy, the theta-angle term in the QCD
action of topological origin can be eliminated by chiral transformations, while
giving still nonzero masses to all quarks. Instead, the effects of such
transformations get transmitted by the rotation to the CKM matrix as the KM
phase giving, for of order unity, a Jarlskog invariant typically of
order as experimentally observed. Strong and weak CP violations
appear then as just two facets of the same phenomenon.Comment: 14 pages, 2 figure
Bottom quark mass and QCD duality
The mass of the bottom quark is analyzed in the context of QCD finite energy sum rules. In contrast to the conventional approach, we use a large momentum expansion of the QCD correlator including terms to order alpha(S)(2)(m(b)(2)/q(2))(6) with the upsilon resonances from e(+)c(-) annihilation data as main input. A stable result m(b)(m(b)) = (4.19 +/- 0.05) GeV for the bottom quark mass is obtained. This result agrees with the independent calculations based on the inverse moment analysis
Search for new physics in semileptonic decays of K and B as implied by the g-2 anomaly in FSM
The framed standard model (FSM), constructed to explain, with some success,
why there should be 3 and apparently only 3 generations of quarks and leptons
in nature falling into a hierarchical mass and mixing pattern, suggests also,
among other things, a scalar boson U, with mass around 17 MeV and small
couplings to quarks and leptons, which might explain the g-2 anomaly reported
in experiment. The U arises in FSM initially as a state in the predicted
`hidden sector' with mass around 17 MeV, which mixes with the standard model
(SM) Higgs , acquiring thereby a coupling to quarks and leptons and a mass
just below 17 MeV. The initial purpose of the present paper is to check whether
this proposal is compatible with experiment on semileptonic decays of Ks and Bs
where the U can also appear. The answer to this we find is affirmative, in that
the contribution of U to new physics as calculated in the FSM remains within
the experimental bounds, but only if lies within a narrow range just
below the unmixed mass. As a result from this, one has an estimate MeV for the mass of , and from some further considerations the
estimate eV for its width, both of which may be useful for
an eventual search for it in experiment. And, if found, it will be, for the
FSM, not just the discovery of a predicted new particle, but the opening of a
window into a whole ``hidden sector" containing at least some, perhaps ven the
bulk, of the dark matter in the universe
New Angle on the Strong CP and Chiral Symmetry Problems from a Rotating Mass Matrix
It is shown that when the mass matrix changes in orientation (rotates) in
generation space for changing energy scale, then the masses of the lower
generations are not given just by its eigenvalues. In particular, these masses
need not be zero even when the eigenvalues are zero. In that case, the strong
CP problem can be avoided by removing the unwanted term by a chiral
transformation in no contradiction with the nonvanishing quark masses
experimentally observed. Similarly, a rotating mass matrix may shed new light
on the problem of chiral symmetry breaking. That the fermion mass matrix may so
rotate with scale has been suggested before as a possible explanation for
up-down fermion mixing and fermion mass hierarchy, giving results in good
agreement with experiment.Comment: 14 page
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