Using LEP1, SLD and LEP2 data, for tau lepton production, and data from
p
p
̄
colliders and LEP2, for
W decays into tau leptons, we set model independent limits on non-standard electromagnetic and ...weak magnetic moments of the tau lepton. The most general effective Lagrangian giving rise to tau moments is used without further assumptions. Precise bounds (2
σ) on the non-standard model contributions to tau electromagnetic (−0.007<
a
γ
<0.005), tau
Z-magnetic (−0.0024<
a
Z
<0.0025) and tau
W-magnetic (−0.003<
κ
W
<0.004) dipole moments are set from the analysis.
The Tau-lepton electric dipole moment (EDM) can be measured at Super B/Flavor factories operating with polarized electron beams at energies near and on top of the resonances. In particular, new ...CP-odd observables, independent from others already considered, will allow to put stringent bounds on the τ EDM.
The electric and weak electric dipole form factors for heavy fermions are calculated in the context of the most general two Higgs doublet model (2HDM). We find that a large top mass can produce a ...significant enhancement of the electric dipole form factor in the case of the b and c quarks. This effect can be used to distinguish between different 2HDM scenarios.
Anomalous top magnetic couplings GONZÁLEZ-SPRINBERG, G; MARTINEZ, R; VIDAL, JORGE
Pramāṇa,
11/2012, Letnik:
79, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the
tbW
vertex in the Standard Model (SM) are computed.
We compute the multidegrees and the Segre numbers of general determinantal Cremona transformations, with generically reduced base scheme, by specializing to the standard Cremona transformation and ...computing its Segre class via mixed volumes of rational polytopes.
The tau weak-magnetic dipole moment Bernabéu, J.; González-Sprinberg, G.A.; Tung, M. ...
Nuclear physics. B,
02/1995, Letnik:
436, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We calculate the prediction for the anomalous weak-magnetic form factor of the tau lepton at
q
2 =
M
2 within the Standard Model. With all particles on-shell, this is an electroweak gauge-invariant ...quantity. Its value is
a
τ
w
(
M
Z
2)= − (2.10+0.61
i) × 10
−6. We show that the transverse and normal components of the single-tau polarization of tau pairs produced at
e
+
e
− unpolarized collisions are sensitive to the real and absorptive parts of the anomalous weak-magnetic dipole moment of the tau. The sensitivity one can achieve at LEP in the measurement of this dipole moment is discussed.
We describe the group structure of monomial Cremona transformations. It follows that every element of this group is a product of quadratic monomial transformations, and geometric descriptions in ...terms of fans.
Descrevemos a estrutura do grupo das transformações de Cremona monomiais. Concluímos que todo elemento deste grupo é um produto de aplicações monomiais quadráticas e damos descrições geométricas em termos de leques.
With initial and final particles on-shell, the anomalous weak-magnetic dipole moments of
b and
c quarks are electroweak gauge invariant quantities of the effective couplings
Zb
b
and
Zc
c
, ...respectively, and good candidates to test the Standard Model and/or new physics. Here we present a complete computation of these quantities within the Standard Model. We show that decoupling properties with respect to heavy particles do take place in the weak magnetic moment. The obtained values,
a
b
(
M
Z
2) = (2.98 − 1.56
i) × 10
−4 and
a
c
(
M
Z
2) = (−2.80 + 1.09
i) × 10
−5 are dominated by one-gluon exchange diagrams. The electroweak corrections are less than 1% of the total magnitude.
PDF
