8,716 research outputs found
Endogenous Lobbying
In this paper we endogenize the number and characteristics of lobbies in a citizen-candidate model of representative democracy where citizens can lobby an elected policy-maker. We find that lobbying always matters. That is, lobbying always affects equilibrium policy outcomes. Moreover, only one policy outcome emerges in equilibrium. An "extremist" candidate is elected and implements a "centrist" policy that differs from the one most preferred by the median voter. These results are in contrast with the ones obtained in the context of a citizen-candidate model where lobbies are exogenous.LOBBYING; ELECTIONS
Revisiting the production of ALPs at B-factories
In this paper, the production of Axion-Like Particles (ALPs) at B-factories via the process e+e− → γa is revisited. To this purpose, the relevant cross-section is computed via an effective Lagrangian with simultaneous ALP couplings to b-quarks and photons. The interplay between resonant and non-resonant contributions is shown to be relevant for experiments operating at s=mϒ(nS), with n = 1, 2, 3, while the non-resonant one dominates at ϒ(4S). These effects imply that the experimental searches performed at different quarkonia resonances are sensitive to complementary combinations of ALP couplings. To illustrate these results, constraints from existing BaBar and Belle data on ALPs decaying into invisible final states are derived, and the prospects for the Belle-II experiment are discussedThe authors acknowledge F. Anulli, D. Becirevic, S. Fajfer, A. Guerrera, C. Hearty,
S.J.D. King, T. Ferben, S. Lacaprara, M. Margoni, F. Mescia, M. Passera and P. Paradisi for very useful exchanges. This project has received support by the European Union’s
Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant
agreement N◦ 674896 (ITN Elusives) and 690575 (RISE InvisiblePlus) and by the exchange
of researchers project “The flavor of the invisible universe” funded by the Italian Ministry
of Foreign Affairs and International Cooperation (MAECI). L.M. acknowledges partial
financial support by the Spanish MINECO through the “Ram´on y Cajal” programme
(RYC-2015-17173), by the Spanish “Agencia Estatal de Investigaci´on” (AEI) and the EU
“Fondo Europeo de Desarrollo Regional” (FEDER) through the project FPA2016-78645-P,
and through the Centro de excelencia Severo Ochoa Program under grant SEV-2016-0597.
L.M. thanks the Physics and Astronomy Department ‘G.Galilei’ of the Universit`a degli
Studi di Padova for hospitality during the development of this projec
On the Potential of Leptonic Minimal Flavour Violation
Minimal Flavour Violation can be realized in several ways in the lepton
sector due to the possibility of Majorana neutrino mass terms. We derive the
scalar potential for the fields whose background values are the Yukawa
couplings, for the simplest See-Saw model with just two right-handed neutrinos,
and explore its minima. The Majorana character plays a distinctive role: the
minimum of the potential allows for large mixing angles -in contrast to the
simplest quark case- and predicts a maximal Majorana phase. This points in turn
to a strong correlation between neutrino mass hierarchy and mixing pattern.Comment: 6 pages; version published on Physics Letters
Revisiting Minimal Lepton Flavour Violation in the Light of Leptonic CP Violation
The Minimal Lepton Flavour Violation (MLFV) framework is discussed after the
recent indication for CP violation in the leptonic sector. Among the three
distinct versions of MLFV, the one with degenerate right-handed neutrinos will
be disfavoured, if this indication is confirmed. The predictions for leptonic
radiative rare decays and muon conversion in nuclei are analysed, identifying
strategies to disentangle the different MLFV scenarios. The claim that the
present anomalies in the semi-leptonic -meson decays can be explained within
the MLFV context is critically re-examined concluding that such an explanation
is not compatible with the present bounds from purely leptonic processes.Comment: 36 pages, 4 figures. V2: References added; version accepted for
publication on JHE
Analysis of General Power Counting Rules in Effective Field Theory
We derive the general counting rules for a quantum effective field theory
(EFT) in dimensions. The rules are valid for strongly and weakly
coupled theories, and predict that all kinetic energy terms are canonically
normalized. They determine the energy dependence of scattering cross sections
in the range of validity of the EFT expansion. We show that the size of cross
sections is controlled by the power counting of EFT, not by chiral
counting, even for chiral perturbation theory (PT). The relation between
and is generalized to dimensions. We show that the
naive dimensional analysis counting is related to counting. The
EFT counting rules are applied to PT, low-energy weak interactions,
Standard Model EFT and the non-trivial case of Higgs EFT.Comment: V2: more details and examples added; version published in journal. 17
pages, 4 figures, 2 table
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