264 research outputs found
Dilaton Interactions and the Anomalous Breaking of Scale Invariance of the Standard Model
We discuss the main features of dilaton interactions for fundamental and
effective dilaton fields. In particular, we elaborate on the various ways in
which dilatons can couple to the Standard Model and on the role played by the
conformal anomaly as a way to characterize their interactions. In the case of a
dilaton derived from a metric compactification (graviscalar), we present the
structure of the radiative corrections to its decay into two photons, a photon
and a , two gauge bosons and two gluons, together with their
renormalization properties. We prove that, in the electroweak sector, the
renormalization of the theory is guaranteed only if the Higgs is conformally
coupled. For such a dilaton, its coupling to the trace anomaly is quite
general, and determines, for instance, an enhancement of its decay rates into
two photons and two gluons. We then turn our attention to theories containing a
non-gravitational (effective) dilaton, which, in our perturbative analysis,
manifests as a pseudo-Nambu Goldstone mode of the dilatation current ().
The infrared coupling of such a state to the two-photons and to the two-gluons
sector, and the corresponding anomaly enhancements of its decay rates in these
channels, is critically analyzed.Comment: Revised version, 42 pages, 5 figure
Quark-hadron duality, axial anomaly and mixing
Interplay between axial anomaly and quark-hadron duality in the presence of
strong mixing is considered. The anomaly sum rule for meson transition form
factors based on the dispersive representation of axial anomaly and
quark-hadron duality in octet channel is analyzed. The comparison of this sum
rule to the experimental data on and mesons transition form
factors shows that the interval of duality in this channel is rather small,
contradicting the usual understanding of quark-hadron duality. The same values
of interval of duality are supported by considering the two-point correlator in
the local duality limit. This contradiction may be resolved by introducing of
some nonperturbative non-OPE correction to the relevant spectral density. The
form and value of this correction are discussed.Comment: 9 pages, 1 figure, reference adde
Two photon decay of the pseudoscalars, the chiral symmetry breaking corrections
The extrapolation of the decay amplitudes of the pseudoscalar mesons into two
photons from the soft meson limit where it is obtained from the axial-anomaly
to the mass shell involves the contribution of the 0^ - continuum. These chiral
symmetry breaking corrections turn out to be large. The effects of these
corrections on the calculated pi ^0 decay rate, on the values of the
singlet-octet mixing angle and on the ratios f_8 / f_pi and f_0 / f_pi are
discussed. The implications for the transition form factors gamma gamma* -->
pseudoscalars are also evaluated and confronted with the available experimental
data.Comment: Computational errors straightened and study of the implications on
the form factors of the transitions gamma gamma* --> pseudoscalars adde
Symmetry preserving regularization with a cutoff
A Lorentz and gauge symmetry preserving regularization method is proposed in
4 dimension based on momentum cutoff. We use the conditions of gauge invariance
or freedom of shift of the loop-momentum to define the evaluation of the terms
carrying Lorentz indices, e.g. proportional to k_{\mu}k_{\nu}. The remaining
scalar integrals are calculated with a four dimensional momentum cutoff. The
finite terms (independent of the cutoff) are unambiguous and agree with the
result of dimensional regularization.Comment: 12 pages, 1 figure, v2 references adde
The Higgs resonance in vector boson scattering
A heavy Higgs resonance is described in a representation-independent way
which is valid for the whole energy range of 2 -> 2 scattering processes,
including the asymptotic behavior at low and high energies. The low-energy
theorems which follow from to the custodial SU_2 symmetry of the Higgs sector
restrict the possible parameterizations of the lineshape that are consistent in
perturbation theory. Matching conditions are specified which are necessary and
sufficient to relate the parameters arising in different expansions. The
construction is performed explicitly up to next-to-leading order.Comment: 25 pages, revtex, uses epsf, amssym
Idiopathic isolated clitoromegaly: A report of two cases
BACKGROUND: Clitoromegaly is a frequent congenital malformation, but acquired clitoral enlargement is relatively rare. METHODS: Two acquired clitoromegaly cases treated in AtatĂĽrk Training Hospital, Izmir, Turkey are presented. RESULTS: History from both patients revealed clitoromegaly over the last three years. Neither gynecological nor systemic abnormalities were detected in either patient. Karyotype analyses and hormonal tests were normal. Abdominal and gynaecological ultrasound did not show any cystic lesion or other abnormal finding. Computerized tomography scan of the adrenal glands was normal. Clitoroplasty with preservation of neurovascular pedicles was performed for the treatment of clitoromegaly. CONCLUSION: The patients were diagnosed as "idiopathic isolated" clitoromegaly. To the best of our knowledge, there has been no detailed report about idiopathic clitoromegaly in the literature
The effects of violence and aggression from parents on child protection workers' personal, family and professional lives
Creative Commons CC-BY: This article is distributed under the terms of the Creative Commons Attribution 3.0 License (http://www.creativecommons.org/licenses/by/3.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).This article presents findings from a survey of the experiences of child protection workers in England when working with parents who exhibit aggression and violence. This work explores the effects on workers in their professional lives, and on themselves and their families in their private lives. The article examines workers’ thoughts and experiences about the effects of parental hostility on workers’ ability to protect children. The article also details workers’ experiences of the nature and effectiveness of training and support in this area. These findings are then examined in the light of the results of an analysis of the literature, including the findings from serious case review (SCR) reports in England (official inquiries into the causes of child deaths where the children are known to social and health services). The majority of the 590 respondents in the survey were social workers (n = 402; 68%), reflecting the fact that case management of child protection cases in the United Kingdom is the responsibility of social workers working in statutory agencies. This article addresses, from a consideration of the secondary analysis and the original research findings from the survey, how individual workers, managers, and agencies can best understand and then respond effectively to aggressive parental behaviors.Peer reviewe
Expression of excess receptors and negative feedback control of signal pathways are required for rapid activation and prompt cessation of signal transduction
Cellular signal transduction is initiated by the binding of extracellular ligands to membrane receptors. Receptors are often expressed in excess, and cells are activated when a small number of receptors bind ligands. Intracellular signal proteins are act
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