Constraining the Λ\LambdaCDM and Galileon models with recent cosmological data

The Galileon theory belongs to the class of modified gravity models that can explain the late-time accelerated expansion of the Universe. In previous works, cosmological constraints on the Galileon model were derived, both in the uncoupled case and with a disformal coupling of the Galileon field to matter. There, we showed that these models agree with the most recent cosmological data. In this work, we used updated cosmological data sets to derive new constraints on Galileon models, including the case of a constant conformal Galileon coupling to matter. We also explored the tracker solution of the uncoupled Galileon model. After updating our data sets, especially with the latest \textit{Planck} data and BAO measurements, we fitted the cosmological parameters of the $\Lambda$CDM and Galileon models. The same analysis framework as in our previous papers was used to derive cosmological constraints, using precise measurements of cosmological distances and of the cosmic structure growth rate. We showed that all tested Galileon models are as compatible with cosmological data as the $\Lambda$CDM model. This means that present cosmological data are not accurate enough to distinguish clearly between both theories. Among the different Galileon models, we found that a conformal coupling is not favoured, contrary to the disformal coupling which is preferred at the $2.3\sigma$ level over the uncoupled case. The tracker solution of the uncoupled Galileon model is also highly disfavoured due to large tensions with supernovae and \textit{Planck}+BAO data. However, outside of the tracker solution, the general uncoupled Galileon model, as well as the general disformally coupled Galileon model, remain the most promising Galileon scenarios to confront with future cosmological data. Finally, we also discuss constraints coming from Lunar Laser Ranging experiment and gravitational wave speed of propagation.Comment: 22 pages, 17 figures, published version in A&

Experimental constraints on the uncoupled Galileon model from SNLS3 data and other cosmological probes

The Galileon model is a modified gravity theory that may provide an explanation for the accelerated expansion of the Universe. This model does not suffer from instabilities or ghost problems (normally associated with higher-order derivative theories), restores local General Relativity -- thanks to the Vainshtein screening effect -- and predicts late time acceleration of the expansion. In this paper, we derive a new definition of the Galileon parameters that allows us to avoid having to choose initial conditions for the Galileon field, and then test this model against precise measurements of the cosmological distances and the rate of growth of cosmic structures. We observe a small tension between the constraints set by growth data and those from distances. However, we find that the Galileon model remains consistent with current observations and is still competitive with the \Lambda CDM model, contrary to what was concluded in recent publications.Comment: 19 pages, 15 figures, accepted to Astronomy and Astrophysic

First experimental constraints on the disformally coupled Galileon model

The Galileon model is a modified gravity model that can explain the late-time accelerated expansion of the Universe. In a previous work, we derived experimental constraints on the Galileon model with no explicit coupling to matter and showed that this model agrees with the most recent cosmological data. In the context of braneworld constructions or massive gravity, the Galileon model exhibits a disformal coupling to matter, which we study in this paper. After comparing our constraints on the uncoupled model with recent studies, we extend the analysis framework to the disformally coupled Galileon model and derive the first experimental constraints on that coupling, using precise measurements of cosmological distances and the growth rate of cosmic structures. In the uncoupled case, with updated data, we still observe a low tension between the constraints set by growth data and those from distances. In the disformally coupled Galileon model, we obtain better agreement with data and favour a non-zero disformal coupling to matter at the $2.5\sigma$ level. This gives an interesting hint of the possible braneworld origin of Galileon theory.Comment: 9 pages, 6 figures, updated versio

2023 Updated MASCC/ESMO Consensus Recommendations: prevention of radiotherapy-and chemoradiotherapy-induced nausea and vomiting

Purpose Radiotherapy and chemoradiotherapy-induced nausea and vomiting (RINV and C-RINV) are common and distressing, and there is a need for guidance for clinicians to provide up to date optimal antiemetic prophylaxis and treatment. Through a comprehensive review of the literature concerning RINV and C-RINV, this manuscript aims to update the evidence for antiemetic prophylaxis and rescue therapy and provide a new edition of recommendations for the MASCC/ESMO antiemetic guidelines for RINV and C-RINV. Methods A systematic review of the literature including data published from May 1, 2015, to January 31, 2023, was performed. All authors assessed the literature. Results The searches yielded 343 references; 37 met criteria for full article review, and 20 were ultimately retained. Only one randomized study in chemoradiation had the impact to provide new recommendations for the antiemetic guideline. Based on expert consensus, it was decided to change the recommendation for the “low emetic risk” category from “prophylaxis or rescue” to “rescue” only, while the drugs of choice remain unchanged. Conclusion As for the previous guideline, the serotonin receptor antagonists are still the cornerstone in antiemetic prophylaxis of nausea and vomiting induced by high and moderate emetic risk radiotherapy. The guideline update provides new recommendation for the management of C-RINV for radiotherapy and concomitant weekly cisplatin. To avoid overtreatment, antiemetic prophylaxis is no longer recommended for the “low emetic risk” category

Two superluminous supernovae from the early universe discovered by the Supernova Legacy Survey

We present spectra and lightcurves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M_U = -22.7 is one of the most luminous SNe ever observed, and gives a rare glimpse into the restframe ultraviolet where these supernovae put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but based on the supernova spectrum, we estimate it to be at z ~ 1.5. Both supernovae have similar observer-frame griz lightcurves, which map to restframe lightcurves in the U-band and UV, rising in ~ 20 restframe days or longer, and declining over a similar timescale. The lightcurves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra to theoretical models, and identify lines of C II, C III, Fe III, and Mg II in the spectrum of SNLS 06D4eu and SCP 06F6, and find that they are consistent with an expanding explosion of only a few solar masses of carbon, oxygen, and other trace metals. Thus the progenitors appear to be related to those suspected for SNe Ic. A high kinetic energy, 10^52 ergs, is also favored. Normal mechanisms of powering core- collapse or thermonuclear supernovae do not seem to work for these supernovae. We consider models powered by 56Ni decay and interaction with circumstellar material, but find that the creation and spin-down of a magnetar with a period of 2ms, magnetic field of 2 x 10^14 Gauss, and a 3 solar mass progenitor provides the best fit to the data.Comment: ApJ, accepted, 43 pages, 15 figure

Squark Loop Correction to W^{+-} H^{-+} Associated Hadroproduction

We study the squark loop correction to W^{+-} H^{-+} associated hadroproduction via gluon-gluon fusion within the minimal supersymmetric extension of the standard model. We list full analytic results and quantitatively analyze the resulting shift in the cross section at the CERN Large Hadron Collider assuming a supergravity-inspired scenario.Comment: 13 pages (Latex), 5 figures (Postscript

Naturalness and Higgs Decays in the MSSM with a Singlet

The simplest extension of the supersymmetric standard model - the addition of one singlet superfield - can have a profound impact on the Higgs and its decays. We perform a general operator analysis of this scenario, focusing on the phenomenologically distinct scenarios that can arise, and not restricting the scope to the narrow framework of the NMSSM. We reexamine decays to four b quarks and four tau's, finding that they are still generally viable, but at the edge of LEP limits. We find a broad set of Higgs decay modes, some new, including those with four gluon final states, as well as more general six and eight parton final states. We find the phenomenology of these scenarios is dramatically impacted by operators typically ignored, specifically those arising from D-terms in the hidden sector, and those arising from weak-scale colored fields. In addition to sensitivity of m_Z, there are potential tunings of other aspects of the spectrum. In spite of this, these models can be very natural, with light stops and a Higgs as light as 82 GeV. These scenarios motivate further analyses of LEP data as well as studies of the detection capabilities of future colliders to the new decay channels presented.Comment: 3 figures, 1 appendix; version to appear in JHEP; typos fixed and additional references and acknowledgements adde

An Efficient Approach to Obtaining Large Numbers of Distant Supernova Host Galaxy Redshifts

We use the wide-field capabilities of the 2dF fibre positioner and the AAOmega spectrograph on the Anglo-Australian Telescope (AAT) to obtain redshifts of galaxies that hosted supernovae during the first three years of the Supernova Legacy Survey (SNLS). With exposure times ranging from 10 to 60 ksec per galaxy, we were able to obtain redshifts for 400 host galaxies in two SNLS fields, thereby substantially increasing the total number of SNLS supernovae with host galaxy redshifts. The median redshift of the galaxies in our sample that hosted photometrically classified Type Ia supernovae (SNe Ia) is 0.77, which is 25% higher than the median redshift of spectroscopically confirmed SNe Ia in the three-year sample of the SNLS. Our results demonstrate that one can use wide-field fibre-fed multi-object spectrographs on 4m telescopes to efficiently obtain redshifts for large numbers of supernova host galaxies over the large areas of sky that will be covered by future high-redshift supernova surveys, such as the Dark Energy Survey.Comment: 22 pages, 4 figures, accepted for publication in PAS