0000000001203458
AUTHOR
O. Vives
showing 10 related works from this author
Flavour-changing Higgs decays into bottom and strange quarks in supersymmetry
2015
In this work, we explore the flavour changing decays $H_i \to b s$ in a general supersymmetric scenario. In these models, the flavour changing decays arise at loop-level but, originating from a dimension-four operator, do not decouple and may provide a first sign of new physics for heavy masses beyond collider reach. In the framework of the minimal supersymmetric extension of the Standard Model (MSSM), we find that the largest branching ratio of the lightest Higgs ($H_1$) is ${\cal O}(10^{-6})$ after imposing present experimental constraints. While heavy Higgs states may still present branching ratios ${\cal O}(10^{-3})$. In a more general supersymmetric scenario, where additional Higgs sta…
Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production
2019
MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb$^{-1}$ of 13 TeV proton-proton collisions at the LHC…
Gamma-Z interferometry at a phi-factory
1995
We analyze the possibilities that the proposed $\Phi$-factories offer to measure $\gamma-Z$ interference. In the unpolarized beam case, we study different signatures in the $\rho \pi$ channel, taking advantage of the presence of the near-by $a_1$ resonance. We build a C-odd forward-backward asymmetry, estimated to be around $10^{-5}$, and (P-even, T-even) and (P-odd, T-odd) alignments of the $\rho$, to be seen from the angular distribution of its $\pi \pi$ decay products. With polarized electrons a left-right asymmetry around $2\times 10^{-4}$ is present in all channels. At leading order this asymmetry is independent of hadronic matrix elements and is sensitive to the $Z^0-s\bar{s}$ vector …
Physics demos for all UVEG degrees: a unique project in Spain
2016
Abstract The Physics Demo Project at the University of Valencia ( www.uv.es/fisicademos ) has developed a collection of physics demonstrations to be used during lectures. It consists of more than 130 experimental demos about different physics topics. More than 30 professors borrow them whenever they lecture on physics in any of our 40 courses in 17 different science or technical degrees, involving 246 ECTS and more than 3500 students. Each demo kit with a simple experimental set displays a particular physics phenomenon. An on-line user guide highlights the main physics principles involved, instructions on how to use it and advices of how to link it to the theoretical concepts or to technica…
On the full Boltzmann equations for leptogenesis
2009
We consider the full Boltzmann equations for standard and soft leptogenesis, instead of the usual integrated Boltzmann equations which assume kinetic equilibrium for all species. Decays and inverse decays may be inefficient for thermalising the heavy-(s)neutrino distribution function, leading to significant deviations from kinetic equilibrium. We analyse the impact of using the full kinetic equations in the case of a previously generated lepton asymmetry, and find that the washout of this initial asymmetry due to the interactions of the right-handed neutrino is larger than when calculated via the integrated equations. We also solve the full Boltzmann equations for soft leptogenesis, where t…
METing SUSY on the Z peak
2016
Recently the ATLAS experiment announced a 3 $\sigma$ excess at the Z-peak consisting of 29 pairs of leptons together with two or more jets, $E_T^{\rm miss}> 225$ GeV and $H_T \geq 600$ GeV, to be compared with $10.6 \pm 3.2$ expected lepton pairs in the Standard Model. No excess outside the Z-peak was observed. By trying to explain this signal with SUSY we find that only relatively light gluinos, $m_{\tilde g} \lesssim 1.2$ TeV, together with a heavy neutralino NLSP of $m_{\tilde \chi} \gtrsim 400$ GeV decaying predominantly to Z-boson plus a light gravitino, such that nearly every gluino produces at least one Z-boson in its decay chain, could reproduce the excess. We construct an explicit …
Prospects for discovering supersymmetric long-lived particles with MoEDAL
2020
We present a study on the possibility of searching for long-lived supersymmetric partners with the MoEDAL experiment at the LHC. MoEDAL is sensitive to highly ionising objects such as magnetic monopoles or massive (meta)stable electrically charged particles. We focus on prospects of directly detecting long-lived sleptons in a phenomenologically realistic model which involves an intermediate neutral long-lived particle in the decay chain. This scenario is not yet excluded by the current data from ATLAS or CMS, and is compatible with astrophysical constraints. Using Monte Carlo simulation, we compare the sensitivities of MoEDAL versus ATLAS in scenarios where MoEDAL could provide discovery re…
Tree-level flavor-changing neutral currents in the B system: From CP asymmetries to rare decays
2001
Tree-level flavor-changing neutral currents (FCNC) are characteristic of models with extra vectorlike quarks. These new couplings can strongly modify the B/sup 0/ CP asymmetries without conflicting with low-energy constraints. In the light of low CP asymmetry in B to J/ psi K/sub S/, we discuss the implications of these contributions. We find that even these low values can be easily accommodated in these models. Furthermore, we show that the new data from B factories tend to favor an O(20) enhancement of the b to dll transition over the SM expectation. (25 refs).
Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC
2016
The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area $\sim$18 m$^2$, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trap…
Improved $\tau$-weapons for Higgs hunting
2013
In this work, we use the results from Higgs searches in the $\gamma\gamma$ and $\tau\tau$ decay channels at LHC and indirect bounds as BR$(B \to X_s \gamma)$ to constrain the parameter space of a generic MSSM Higgs sector. In particular, we include the latest CMS results that look for additional Higgs states with masses up to 1 TeV. We show that the $\tau \tau$ channel is the best and most accurate weapon in the hunt for new Higgs states beyond the Standard Model. We obtain that present experimental results rule out additional neutral Higgs bosons in a generic MSSM below 300 GeV for any value of $\tan \beta$ and, for instance, values of $\tan \beta$ above 30 are only possible for Higgs mass…