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Author MoEDAL Collaboration (Acharya, B. et al); Bernabeu, J.; Garcia, C.; King, M.; Mitsou, V.A.; Vento, V.; Vives, O. url  doi
openurl 
  Title Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC Type Journal Article
  Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 08 Issue 8 Pages 067 - 25pp  
  Keywords Exotics; Hadron-Hadron scattering (experiments); Particle and resonance production  
  Abstract 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 similar to 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 trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb(-1). No magnetic charge exceeding 0.5g(D) (where g(D) is the Dirac magnetic charge) is measured in any of the exposed samples, allowing limits to be placed on monopole production in the mass range 100 GeV <= m <= 3500 GeV. Model-independent cross-section limits are presented in fiducial regions of monopole energy and direction for 1g(D) <= vertical bar g vertical bar <= 6g(D), and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for 1g(D) <= vertical bar g vertical bar <= 4g(D). Under the assumption of Drell-Yan cross sections, mass limits are derived for vertical bar g vertical bar = 2g(D) and vertical bar g vertical bar = 3g(D) for the first time at the LHC, surpassing the results from previous collider experiments.  
  Address [Acharya, B.; Alexandre, J.; Ellis, J. R.; Fairbairn, M.; Mavromatos, N. E.; Sakellariadou, M.; Sarkar, S.] Kings Coll London, Dept Phys, Theoret Particle Phys & Cosmol Grp, London, England, Email: philippe.mermod@cern.ch  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000391754500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2927  
Permanent link to this record
 
 
Author MoEDAL Collaboration (Acharya, B. et al); Bernabeu, J.; Garcia, C.; Mamuzic, J.; Mitsou, V.A.; Ruiz de Austri, R.; Vento, V.; Vives, O. url  doi
openurl 
  Title Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC Type Journal Article
  Year 2017 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 118 Issue 6 Pages 061801 - 6pp  
  Keywords  
  Abstract MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.  
  Address [Acharya, B.; Alexandre, J.; Ellis, J. R.; Fairbairn, M.; Mavromatos, N. E.; Sakellariadou, M.; Sarkar, S.] Kings Coll London, Dept Phys, Theoret Particle Phys & Cosmol Grp, London, England, Email: philippe.mermod@cern.ch  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9007 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000393747300004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2969  
Permanent link to this record
 
 
Author Aguilar-Saavedra, J.A.; Bernabeu, J.; Mitsou, V.A.; Segarra, A. url  doi
openurl 
  Title The Z boson spin observables as messengers of new physics Type Journal Article
  Year 2017 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C  
  Volume 77 Issue 4 Pages 234 - 6pp  
  Keywords  
  Abstract We demonstrate that the eight multipole parameters describing the spin state of the Z boson are able to disentangle known Z production mechanisms and signals from new physics at the LHC. They can be extracted from appropriate asymmetries in the angular distribution of lepton pairs from the Z boson decay. The power of this analysis is illustrated by (1) the production of Z boson plus jets; (2) Z boson plus missing transverse energy; (3) W and Z bosons originating from the two-body decay of a heavy resonance.  
  Address [Aguilar-Saavedra, J. A.] Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain, Email: jaas@ugr.es  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1434-6044 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000399448700004 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3121  
Permanent link to this record
 
 
Author Kuehn, S. et al; Bernabeu, J.; Lacasta, C.; Marco-Hernandez, R.; Santoyo, D.; Solaz, C.; Soldevila, U. doi  openurl
  Title Prototyping of hybrids and modules for the forward silicon strip tracking detector for the ATLAS Phase-II upgrade Type Journal Article
  Year 2017 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.  
  Volume 12 Issue Pages P05015 - 26pp  
  Keywords Si microstrip and pad detectors; Particle tracking detectors (Solid-state detectors); Solid state detectors  
  Abstract For the High-Luminosity upgrade of the Large Hadron Collider an increased instantaneous luminosity of up to 7.5 . 10(34) cm(-2) s(-1), leading to a total integrated luminosity of up to 3000 fb(-1), is foreseen. The current silicon and transition radiation tracking detectors of the ATLAS experiment will be unable to cope with the increased track densities and radiation levels, and will need to be replaced. The new tracking detector will consist entirely of silicon pixel and strip detectors. In this paper, results on the development and tests of prototype components for the new silicon strip detector in the forward regions (end-caps) of the ATLAS detector are presented. Flex-printed readout boards with fast readout chips, referred to as hybrids, and silicon detector modules are investigated. The modules consist of a hybrid glued onto a silicon strip sensor. The channels on both are connected via wire-bonds for readout and powering. Measurements of important performance parameters and a comparison of two possible readout schemes are presented. In addition, the assembly procedure is described and recommendations for further prototyping are derived.  
  Address [Kuehn, S.] CERN, European Org Nucl Res, Expt Phys, Route Meyrin 385, CH-1211 Geneva 23, Switzerland, Email: susanne.kuehn@cern.ch  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1748-0221 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000405076000015 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3221  
Permanent link to this record
 
 
Author Bernabeu, J.; Botella, F.J.; Mavromatos, N.E.; Nebot, M. url  doi
openurl 
  Title The signal of ill-defined CPT weakening entanglement in the B-d system Type Journal Article
  Year 2017 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C  
  Volume 77 Issue 12 Pages 865 - 10pp  
  Keywords  
  Abstract In the presence of quantum-gravity fluctuations (space-time foam), the CPT operator may be ill-defined. Its perturbative treatment leads to a modification of the Einstein-Podolsky- Rosen correlation of the neutral meson system by adding an entanglement-weakening term of the wrong exchange symmetry, the omega-effect. In the current paper we identify how to probe the complex omega in the entangled B-d system using the flavour (f)-CP(g) eigenstate decay channels: the connection between the intensities for the two timeordered decays (f, g) and (g, f) is lost. Appropriate observables are constructed allowing independent experimental determinations of Re(omega) and Im(omega), disentangled from CPT violation in the evolution Hamiltonian Re(theta) and Im(theta). 2 sigma tensions for both Re(theta) and Im(omega) are shown to be uncorrelated.  
  Address [Bernabeu, Jose; Botella, Francisco J.; Mavromatos, Nick E.] Univ Valencia, Dept Fis Teor, IFIC, CSIC, E-46100 Burjassot, Spain, Email: Jose.Bernabeu@uv.es;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1434-6044 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000417827300005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3414  
Permanent link to this record
 
 
Author Bernabeu, J.; Segarra, A. url  doi
openurl 
  Title Stimulated transitions in resonant atom Majorana mixing Type Journal Article
  Year 2018 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 02 Issue 2 Pages 017 - 16pp  
  Keywords Neutrino Physics; Beyond Standard Model; Global Symmetries  
  Abstract Massive neutrinos demand to ask whether they are Dirac or Majorana particles. Majorana neutrinos are an irrefutable proof of physics beyond the Standard Model. Neutrinoless double electron capture is not a process but a virtual Delta L = 2 mixing between a parent (A)Z atom and a daughter (A)(Z – 2) excited atom with two electron holes. As a mixing between two neutral atoms and the observable signal in terms of emitted two-hole X-rays, the strategy, experimental signature and background are different from neutrinoless double beta decay. The mixing is resonantly enhanced for almost degeneracy and, under these conditions, there is no irreducible background from the standard two-neutrino channel. We reconstruct the natural time history of a nominally stable parent atom since its production either by nature or in the laboratory. After the time periods of atom oscillations and the decay of the short-lived daughter atom, at observable times the relevant 'stationary" states are the mixed metastable long-lived state and the non-orthogonal short-lived excited state, as well as the ground state of the daughter atom. We find that they have a natural population inversion which is most appropriate for exploiting the bosonic nature of the observed atomic transitions radiation. Among different observables of the atom Majorana mixing, we include the enhanced rate of stimulated X-ray emission from the long-lived metastable state by a high-intensity X-ray beam: a gain factor of 100 can be envisaged at current XFEL facilities. On the other hand, the historical population of the daughter atom ground state can be probed by exciting it with a current pulsed optical laser, showing the characteristic absorption lines: the whole population can be excited in a shorter time than typical pulse duration.  
  Address [Bernabeu, Jose] Univ Valencia, CSIC, Dept Fis Teor, Calle Dr Moliner 50, E-46100 Burjassot, Spain, Email: Jose.Bernabeu@uv.es;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000424101600008 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3475  
Permanent link to this record
 
 
Author Kuehn, S. et al; Bernabeu, J.; Lacasta, C.; Marco-Hernandez, R.; Rodriguez Rodriguez, D.; Santoyo, D.; Solaz, C.; Soldevila Serrano, U. url  doi
openurl 
  Title Prototyping of petalets for the Phase-II upgrade of the silicon strip tracking detector of the ATLAS experiment Type Journal Article
  Year 2018 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.  
  Volume 13 Issue Pages T03004 - 22pp  
  Keywords Particle tracking detectors (Solid-state detectors); Si microstrip and pad detectors; Solid state detectors; Performance of High Energy Physics Detectors  
  Abstract In the high luminosity era of the Large Hadron Collider, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The ITk consists of a silicon pixel and a strip detector and exploits the concept of modularity. Prototyping and testing of various strip detector components has been carried out. This paper presents the developments and results obtained with reduced-size structures equivalent to those foreseen to be used in the forward region of the silicon strip detector. Referred to as petalets, these structures are built around a composite sandwich with embedded cooling pipes and electrical tapes for routing the signals and power. Detector modules built using electronic flex boards and silicon strip sensors are glued on both the front and back side surfaces of the carbon structure. Details are given on the assembly, testing and evaluation of several petalets. Measurement results of both mechanical and electrical quantities are shown. Moreover, an outlook is given for improved prototyping plans for large structures.  
  Address [Kuehn, S.] European Org Nucl Res, CERN, Geneva, Switzerland, Email: susanne.kuehn@cern.ch  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1748-0221 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000428146400003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3530  
Permanent link to this record
 
 
Author Muñoz, E.; Barrio, J.; Bernabeu, J.; Etxebeste, A.; Lacasta, C.; Llosa, G.; Ros, A.; Roser, J.; Oliver, J.F. doi  openurl
  Title Study and comparison of different sensitivity models for a two-plane Compton camera Type Journal Article
  Year 2018 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 63 Issue 13 Pages 135004 - 19pp  
  Keywords Compton camera imaging; MLEM; Monte Carlo simulations; image quality  
  Abstract Given the strong variations in the sensitivity of Compton cameras for the detection of events originating from different points in the field of view (FoV), sensitivity correction is often necessary in Compton image reconstruction. Several approaches for the calculation of the sensitivity matrix have been proposed in the literature. While most of these models are easily implemented and can be useful in many cases, they usually assume high angular coverage over the scattered photon, which is not the case for our prototype. In this work, we have derived an analytical model that allows us to calculate a detailed sensitivity matrix, which has been compared to other sensitivity models in the literature. Specifically, the proposed model describes the probability of measuring a useful event in a two-plane Compton camera, including the most relevant physical processes involved. The model has been used to obtain an expression for the system and sensitivity matrices for iterative image reconstruction. These matrices have been validated taking Monte Carlo simulations as a reference. In order to study the impact of the sensitivity, images reconstructed with our sensitivity model and with other models have been compared. Images have been reconstructed from several simulated sources, including point-like sources and extended distributions of activity, and also from experimental data measured with Na-22 sources. Results show that our sensitivity model is the best suited for our prototype. Although other models in the literature perform successfully in many scenarios, they are not applicable in all the geometrical configurations of interest for our system. In general, our model allows to effectively recover the intensity of point-like sources at different positions in the FoV and to reconstruct regions of homogeneous activity with minimal variance. Moreover, it can be employed for all Compton camera configurations, including those with low angular coverage over the scatterer.  
  Address [Munoz, Enrique; Barrio, John; Bernabeu, Jose; Etxebeste, Ane; Lacasta, Carlos; Llosa, Gabriela; Ros, Ana; Roser, Jorge; Oliver, Josep F.] Univ Valencia, CSIC, Inst Fis Corpuscular, IFIC, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000436390800004 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3639  
Permanent link to this record
 
 
Author MoEDAL Collaboration (Acharya, B. et al); Bernabeu, J.; Garcia, C.; Mamuzic, J.; Mitsou, V.A.; Ruiz de Austri, R.; Santra, A.; Vento, V.; Vives, O. url  doi
openurl 
  Title Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb(-1) of 13 TeV proton-proton collisions at the LHC Type Journal Article
  Year 2018 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 782 Issue Pages 510-516  
  Keywords  
  Abstract We update our previous search for trapped magnetic monopoles in LHC Run 2 using nearly six times more integrated luminosity and including additional models for the interpretation of the data. The MoEDAL forward trapping detector, comprising 222 kg of aluminium samples, was exposed to 2.11 fb(-1) of 13 TeV proton-proton collisions near the LHCb interaction point and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to the Dirac charge or above are excluded in all samples. The results are interpreted in Drell-Yan production models for monopoles with spins 0, 1/2 and 1: in addition to standard point-like couplings, we also consider couplings with momentum-dependent form factors. The search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.  
  Address [Acharya, B.; Alexandre, J.; Baines, S.; Ellis, J. R.; Fairbairn, M.; Mavromatos, N. E.; Sakellariadou, M.; Sarkar, S.] Kings Coll London, Dept Phys, Theoret Particle & Phys Cosmol Grp, London, England, Email: philippe.mermod@cern.ch  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000438486900076 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3664  
Permanent link to this record
 
 
Author Bernabeu, J.; Segarra, A. url  doi
openurl 
  Title Signatures of the genuine and matter-induced components of the CP violation asymmetry in neutrino oscillations Type Journal Article
  Year 2018 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 11 Issue 11 Pages 063 - 26pp  
  Keywords CP violation; Discrete Symmetries; Neutrino Physics  
  Abstract CP asymmetries for neutrino oscillations in matter can be disentangled into the matter-induced CPT-odd (T-invariant) component and the genuine T-odd (CPT-invariant) component. For their understanding in terms of the relevant ingredients, we develop a new perturbative expansion in both m2| without any assumptions between m2 and a, and study the subtleties of the vacuum limit in the two terms of the CP asymmetry, moving from the CPT-invariant vacuum limit a 0 to the T-invariant limit m20. In the experimental region of terrestrial accelerator neutrinos, we calculate their approximate expressions from which we prove that, at medium baselines, the CPT-odd component is small and nearly -independent, so it can be subtracted from the experimental CP asymmetry as a theoretical background, provided the hierarchy is known. At long baselines, on the other hand, we find that (i) a Hierarchy-odd term in the CPT-odd component dominates the CP asymmetry for energies above the first oscillation node, and (ii) the CPT-odd term vanishes, independent of the CP phase , at E = 0.92 GeV (L/1300 km) near the second oscillation maximum, where the T-odd term is almost maximal and proportional to sin . A measurement of the CP asymmetry in these energy regions would thus provide separate information on (i) the neutrino mass ordering, and (ii) direct evidence of genuine CP violation in the lepton sector.  
  Address [Bernabeu, Jose] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: Jose.Bernabeu@uv.es;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000449817300002 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3801  
Permanent link to this record
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