884 research outputs found
CP violating effects in the decay Z -> mu^+mu^-gamma induced by ZZgamma and Zgammagamma couplings
We analyze possible CP-violating effects induced in the decay with hard
photon radiation by and anomalous vertices. We
estimate the sensibility of future linear collider experiments on these
couplings coming from CP-odd asymmetries associated to angular correlations of
the three particle final state in . We find
that a linear collider with an integrated luminosity of 500 and
TeV can place the bound at the 90%
confidence level for these couplings.Comment: Added references, 2 graphics 5 pages, LaTeX; typos added, 4 graphics
remove
The complete theory of Maxwell and Proca fields
We present the most general ghost-free classical Lagrangian containing
first-order derivatives and describing interacting real Abelian spin-one fields
on Minkowski spacetime. We study both massive Proca and massless Maxwell fields
and allow for a non-linear realization of mass, in the form of derivative
self-interactions. Within this context, our construction notoriously extends
the existing literature, which is limited to the case of a single Proca field
and to multiple interacting Proca fields in the presence of a global rotational
symmetry. In the limit of a single Proca field, we reproduce the known healthy
interaction terms. We provide the necessary and sufficient conditions to ensure
ghost-freedom in any multi-field setup. We observe that, in general, the said
conditions are not satisfied by the rotationally symmetric multi-Proca
interactions suggested so far, which implies that they propagate ghosts. Our
theory admits a plethora of applications in a wide range of subjects. For
illustrative purposes, we provide concrete proposals in holographic condensed
matter and black hole physics.Comment: 6 pages. v2: References added. v3: Single Proca limit modified. v4:
Journal version. This work is dedicated to Mar\'{i}a Jos\'{e} D\'{i}ez
Segovian
Decays Z' -> \gamma\gamma\gamma{} and Z -> \gamma\gamma\gamma{} in the minimal 331 model
The possibility of a significant effect of exotic particles on the
Z'->\gamma\gamma\gamma{} and Z->\gamma\gamma\gamma{} decays is investigated in
the context of the minimal 331 model. This model, which is based in the
SU_C(3)xSU_L(3)xU_X(1) gauge group, predicts the existence of many exotic
charged particles that can significantly enhance the decay widths. It is found
that the standard model prediction for the Z->\gamma\gamma\gamma{} decay
remains essentially unchanged, as the new physics effects quickly decouples. On
the other hand, it is found that the contributions of the new exotic quarks and
gauge bosons predicted by this model lead to a branching fraction for the
Z'->\gamma\gamma\gamma{} decay of about 10^(-6), which is about three orders of
magnitude larger than that of the Z->\gamma\gamma\gamma{} decay.Comment: 20 pages and 20 figure
Saline and Alkali Soils in Peru
Black and white 8x10 Acetate Negativehttps://digitalmaine.com/arc_george_french_photos_a810/1495/thumbnail.jp
Effective Lagrangian description of Higgs mediated flavor violating electromagnetic transitions: implications on lepton flavor violation
Higgs mediated flavor violating electromagnetic interactions, induced at the
one--loop level by a nondiagonal vertex, with and charged
leptons or quarks, are studied within the context of a completely general
effective Yukawa sector that comprises --invariant
operators of up to dimension--six. Exact formulae for the one--loop and couplings are presented and their related
processes used to study the phenomena of Higgs mediated lepton flavor
violation. The experimental limit on the decay is used to
derive a bound on the branching ratio of the
transition, which is 6 orders of magnitude stronger than the current
experimental limit. Previous results on the and decays are reproduced. The possibility of detecting signals
of lepton flavor violation at colliders is explored through the
reaction, putting special emphasis on the
final state. Using the bound imposed on the vertex by the current
experimental data on the muon anomalous magnetic moment, it is found that about
half a hundred events may be produced in the International Linear Collider.Comment: 18 pages, 12 figure
Constraint characterization and degree of freedom counting in Lagrangian field theory
We present a Lagrangian approach to counting degrees of freedom in
first-order field theories. The emphasis is on the systematic attainment of a
complete set of constraints. In particular, we provide the first comprehensive
procedure to ensure the functional independence of all constraints and discuss
in detail the possible closures of the constraint algorithm. We argue degrees
of freedom can but need not correspond to physical modes. The appendix
comprises fully worked out, physically relevant examples of varying complexity.Comment: 12 pages + Appendix and Reference
- …