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Dudley, R. A., Anderson, P. R., Balbinot, R., & Fabbri, A. (2018). Correlation patterns from massive phonons in 1+1 dimensional acoustic black holes: A toy model. Phys. Rev. D, 98(12), 124011–18pp.
Abstract: Transverse excitations in analogue black holes induce a masslike term in the longitudinal mode equation. With a simple toy model we show that correlation functions display a rather rich structure characterized by groups of approximately parallel peaks. For the most part the structure is completely different from that found in the massless case.
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Dai, L. R., & Oset, E. (2018). Polarization amplitudes in VP decay beyond the Standard Model. Eur. Phys. J. A, 54(12), 219–10pp.
Abstract: We study the amplitudes of the -VP decay for the different polarizations of the vector meson V, using a formalism where the mapping from the quark degrees of freedom to the meson ones is done with the P-3(0) model. We extend the formalism to a case, with the operator -5, that can account for different models beyond the Standard Model and study in detail the -K*0K- reaction for the different polarizations of the K*0. The results are shown in terms of the parameter that differs for each model. We find that is very different for each of the third components of the vector spin, M=+/- 1,0, and in particular the magnitude |M=-1 is very sensitive to the parameter, which makes the investigation of this magnitude very useful to test different models beyond the Standard Model.
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del Rio, A., Durrer, R., & Patil, S. P. (2018). Tensor bounds on the hidden universe. J. High Energy Phys., 12(12), 094–34pp.
Abstract: During single clock inflation, hidden fields (i.e. fields coupled to the inflaton only gravitationally) in their adiabatic vacua can ordinarily only affect observables through virtual effects. After renormalizing background quantities (fixed by observations at some pivot scale), all that remains are logarithmic runnings in correlation functions that are both Planck and slow roll suppressed. In this paper we show how a large number of hidden fields can partially compensate this suppression and generate a potentially observable running in the tensor two point function, consistently inferable courtesy of a large N resummation. We detour to address certain subtleties regarding loop corrections during inflation, extending the analysis of [1]. Our main result is that one can extract bounds on the hidden field content of the universe from bounds on violations of the consistency relation between the tensor spectral index and the tensor to scalar ratio, were primordial tensors ever detected. Such bounds are more competitive than the naive bound inferred from requiring inflation to occur below the strong coupling scale of gravity if deviations from the consistency relation can be bounded to within the sub-percent level. We discuss how one can meaningfully constrain the parameter space of various phenomenological scenarios and constructions that address naturalness with a large number of species (such as N-naturalness') with CMB observations up to cosmic variance limits, and possibly future 21cm and gravitational wave observations.
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NA48/2 Collaboration(Batley, J. R. et al), & Fiorini, L. (2018). Measurement of the form factors of charged kaon semileptonic decays. J. High Energy Phys., 10(10), 150–23pp.
Abstract: A measurement of the form factors of charged kaon semileptonic decays is presented, based on 4.4 x 10(6)K(+/-) (0)e(e)(+/-) (Ke3 +/-) and 2.3 x 10(6)K(+/-) (0)+/- (K3 +/-) decays collected in 2004 by the NA48/2 experiment. The results are obtained with improved precision as compared to earlier measurements. The combination of measurements in the Ke3 +/- and K3 +/- modes is also presented.
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Baines, S., Mavromatos, N. E., Mitsou, V. A., Pinfold, J. L., & Santra, A. (2018). Monopole production via photon fusion and Drell-Yan processes: MadGraph implementation and perturbativity via velocity-dependent coupling and magnetic moment as novel features. Eur. Phys. J. C, 78(11), 966–36pp.
Abstract: In this work we consider point-like monopole production via photon-fusion and Drell-Yan processes in the framework of an effective U(1) gauge field theory obtained from conventional models describing the interaction of magnetically-charged fields with ordinary photons, upon electric-magnetic dualisation. We present arguments based on such dualities which support the conjecture of an effective monopole-velocity-dependent magnetic charge. For the cases of 1 monopoles, we also include a magnetic-moment which is treated as a new phenomenological parameter and, together with the velocity-dependent coupling, allows for a perturbative treatment of the cross-section calculation. We discuss unitarity issues within these effective field theories, in particular we point out that in the spin-1 monopole case only the may restore unitarity. However from an effective-field-theory point of view, this lack of unitarity should not be viewed as an impediment for the phenomenological studies and experimental searches of generic spin-1 monopoles, given that the potential appearance of new degrees of freedom in the ultraviolet completion of such models might restore it. The second part of the paper deals with an appropriate implementation of photon-fusion and Drell-Yan processes based on the above theoretical scenarios into MadGraph UFO models, aimed to serve as a useful tool in interpretations of monopole searches at colliders such as LHC, especially for photon fusion, given that it has not been considered by experimental collaborations so far. Moreover, the experimental implications of such perturbatively reliable monopole searches have been laid out.
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