Home << 1 2 3 4 5 6 >>
List View
 | 
Citations
 | 
Details
   web
Records
Author Aguilar-Saavedra, J.A.; Bernabeu, J.; Mitsou, V.A.; Segarra, A.
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 Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 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 Bernabeu, J.; Botella, F.J.; Mavromatos, N.E.; Nebot, M.
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 Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 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.; Espinoza, C.; Mavromatos, N.E.
Title Cosmological constant and local gravity Type Journal Article
Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 81 Issue 8 Pages 084002 - 7pp
Keywords
Abstract We discuss the linearization of Einstein equations in the presence of a cosmological constant, by expanding the solution for the metric around a flat Minkowski space-time. We demonstrate that one can find consistent solutions to the linearized set of equations for the metric perturbations, in the Lorentz gauge, which are not spherically symmetric, but they rather exhibit a cylindrical symmetry. We find that the components of the gravitational field satisfying the appropriate Poisson equations have the property of ensuring that a scalar potential can be constructed, in which both contributions, from ordinary matter and Lambda > 0, are attractive. In addition, there is a novel tensor potential, induced by the pressure density, in which the effect of the cosmological constant is repulsive. We also linearize the Schwarzschild-de Sitter exact solution of Einstein's equations ( due to a generalization of Birkhoff's theorem) in the domain between the two horizons. We manage to transform it first to a gauge in which the 3-space metric is conformally flat and, then, make an additional coordinate transformation leading to the Lorentz gauge conditions. We compare our non-spherically symmetric solution with the linearized Schwarzschild-de Sitter metric, when the latter is transformed to the Lorentz gauge, and we find agreement. The resulting metric, however, does not acquire a proper Newtonian form in terms of the unique scalar potential that solves the corresponding Poisson equation. Nevertheless, our solution is stable, in the sense that the physical energy density is positive.
Address [Bernabeu, Jose; Espinoza, Catalina] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Valencia, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1550-7998 ISBN Medium
Area Expedition Conference
Notes ISI:000277205000057 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 460
Permanent link to this record
 
 
Author Bernabeu, J.; Espriu, D.; Puigdomenech, D.
Title Gravitational waves in the presence of a cosmological constant Type Journal Article
Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 84 Issue 6 Pages 063523 - 13pp
Keywords
Abstract We derive the effects of a nonzero cosmological constant Lambda on gravitational wave propagation in the linearized approximation of general relativity. In this approximation, we consider the situation where the metric can be written as g(mu nu) = eta(mu nu) + h(mu nu)(Lambda) + h(mu nu)(W), h(mu nu)(Lambda,W) << 1, where h(mu nu)(Lambda) is the background perturbation and h(mu nu)(W) is a modification interpretable as a gravitational wave. For Lambda not equal 0, this linearization of Einstein equations is self-consistent only in certain coordinate systems. The cosmological Friedmann-Robertson-Walker coordinates do not belong to this class and the derived linearized solutions have to be reinterpreted in a coordinate system that is homogeneous and isotropic to make contact with observations. Plane waves in the linear theory acquire modifications of order root Lambda, both in the amplitude and the phase, when considered in Friedmann-Robertson-Walker coordinates. In the linearization process for h(mu nu), we have also included terms of order O(Lambda h(mu nu)). For the background perturbation h(mu nu)(Lambda), the difference is very small, but when the term h(mu nu)(W)Lambda is retained the equations of motion can be interpreted as describing massive spin-2 particles. However, the extra degrees of freedom can be approximately gauged away, coupling to matter sources with a strength proportional to the cosmological constant itself. Finally, we discuss the viability of detecting the modifications caused by the cosmological constant on the amplitude and phase of gravitational waves. In some cases, the distortion with respect to gravitational waves propagating in Minkowski space-time is considerable. The effect of Lambda could have a detectable impact on pulsar timing arrays.
Address [Bernabeu, J] Univ Valencia, Dept Fis Teor IFIC, CSIC, E-46100 Valencia, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000295223100005 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 766
Permanent link to this record
 
 
Author Aguilar-Saavedra, J.A.; Bernabeu, J.
Title Breaking down the entire W boson spin observables from its decay Type Journal Article
Year 2016 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 93 Issue 1 Pages 011301 - 6pp
Keywords
Abstract We discuss the eight independent spin observables for the W boson in terms of its vector and tensor polarizations and identify the angular distributions and asymmetries able to separate them in collider experiments. The results are applied to the study of polarized top quark decays and diboson resonances. These novel observables are of great value for disentangling new physics mechanisms in W boson production.
Address [Aguilar-Saavedra, J. A.] Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000368324500001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2538
Permanent link to this record
 
 
Author Kuehn, S. et al; Bernabeu, J.; Lacasta, C.; Marco-Hernandez, R.; Santoyo, D.; Solaz, C.; Soldevila, U.
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 Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 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 Kuehn, S. et al; Bernabeu, J.; Lacasta, C.; Marco-Hernandez, R.; Rodriguez Rodriguez, D.; Santoyo, D.; Solaz, C.; Soldevila Serrano, U.
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 Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 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 Poley, L. et al; Bernabeu, J.; Civera, J.V.; Lacasta, C.; Leon, P.; Platero, A.; Platero, V; Solaz, C.; Soldevila, U.; Vidal, G.
Title The ABC130 barrel module prototyping programme for the ATLAS strip tracker Type Journal Article
Year 2020 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.
Volume 15 Issue 9 Pages P09004 - 78pp
Keywords Detector design and construction technologies and materials; Si microstrip and pad detectors; Radiation-hard detectors; Front-end electronics for detector readout
Abstract For the Phase-II Upgrade of the ATLAS Detector [1], its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100% silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-250) [2, 3] and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.
Address [Poley, L.; Anderssen, E.; Ciocio, A.; Cornell, E.; Haber, C.; Haugen, T. E.; Heim, T.; Johnson, T. A.; Krizka, K.; Labitan, C.; Li, B.; Li, C.; MacFadyen, R.; Mladina, E.; Ottino, G.; Sanethavong, P.; Santpur, S. Neha; Witharm, R.] Lawrence Berkeley Natl Lab, Cyclotron Rd, Berkeley, CA 94720 USA, Email: APoley@cern.ch
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1748-0221 ISBN Medium
Area Expedition Conference
Notes WOS:000577273400004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4572
Permanent link to this record
 
 
Author Unno, Y. et al; Bernabeu, J.; Lacasta, C.; Solaz, C.; Soldevila, U.
Title Specifications and pre-production of n plus -in-p large-format strip sensors fabricated in 6-inch silicon wafers, ATLAS18, for the Inner Tracker of the ATLAS Detector for High-Luminosity Large Hadron Collider Type Journal Article
Year 2023 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.
Volume 18 Issue 3 Pages T03008 - 29pp
Keywords Particle tracking detectors (Solid-state detectors); Radiation-hard detectors; Si microstrip and pad detectors
Abstract The ATLAS experiment is constructing new all-silicon inner tracking system for HL-LHC. The strip detectors cover the radial extent of 40 to 100 cm. A new approach is adopted to use p-type silicon material, making the readout in n+-strips, so-called n+-in-p sensors. This allows for enhanced radiation tolerance against an order of magnitude higher particle fluence compared to the LHC. To cope with varying hit rates and occupancies as a function of radial distance, there are two barrel sensor types, the short strips (SS) for the inner 2 and the long strips (LS) for the outer 2 barrel cylinders, respectively. The barrel sensors exhibit a square, 9.8 x 9.8 cm2, geometry, the largest possible sensor area from a 6-inch wafer. The strips are laid out in parallel with a strip pitch of 75.5 μm and 4 or 2 rows of strip segments. The strips are AC-coupled and biased via polysilicon resistors. The endcap sensors employ a “stereo-annulus” geometry exhibiting a skewed-trapezoid shapes with circular edges. They are designed in 6 unique shapes, R0 to R5, corresponding to progressively increasing radial extents and which allows them to fit within the petal geometry and the 6-inch wafer maximally. The strips are in fan-out geometry with an in-built rotation angle, with a mean pitch of approximately 75 μm and 4 or 2 rows of strip segments. The eight sensor types are labeled as ATLAS18xx where xx stands for SS, LS, and R0 to R5. According to the mechanical and electrical specifications, CAD files for wafer processing were laid out, following the successful designs of prototype barrel and endcap sensors, together with a number of optimizations. A pre-production was carried out prior to the full production of the wafers. The quality of the sensors is reviewed and judged excellent through the test results carried out by vendor. These sensors are used for establishing acceptance procedures and to evaluate their performance in the ATLAS collaboration, and subsequently for pre-production of strip modules and stave and petal structures.
Address [Allport, P. P.; Chisholm, A.; George, W.; Gonella, L.; Kopsalis, I.; Lomas, J.] Univ Birmingham, Sch Phys & Astron, Birmingham B152TT, England, Email: yoshinobu.unno@kek.jp
Corporate Author Thesis
Publisher IOP Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1748-0221 ISBN Medium
Area Expedition Conference
Notes WOS:000974242700001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5522
Permanent link to this record
 
 
Author Segarra, A.; Bernabeu, J.
Title Absolute neutrino mass and the Dirac/Majorana distinction from the weak interaction of aggregate matter Type Journal Article
Year 2020 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 101 Issue 9 Pages 093004 - 6pp
Keywords
Abstract The 2 nu-mediated force has a range of microns, well beyond the atomic scale. The effective potential is built from the t-channel absorptive part of the scattering amplitude and depends on neutrino properties on shell. We demonstrate that neutral aggregate matter has a weak charge and calculate the matrix of six coherent charges for its interaction with definite-mass neutrinos. Near the range of the potential the neutrino pair is nonrelativistic, leading to observable absolute mass and Dirac/Majorana distinction via different r-dependence and violation of the weak equivalence principle.
Address [Segarra, Alejandro] Univ Valencia, Dept Theoret Phys, E-46100 Valencia, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000532654200001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4397
Permanent link to this record