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Author Esteban-Pretel, A.; Tomas, R.; Valle, J.W.F.
Title Interplay between collective effects and nonstandard interactions of supernova neutrinos Type Journal Article
Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 81 Issue 6 Pages 063003 - 16pp
Keywords
Abstract We consider the effect of nonstandard neutrino interactions (NSI, for short) on the propagation of neutrinos through the supernova (SN) envelope within a three-neutrino framework and taking into account the presence of a neutrino background. We find that for given NSI parameters, with strength generically denoted by epsilon(ij), neutrino evolution exhibits a significant time dependence. For vertical bar epsilon(tau tau)vertical bar greater than or similar to 10(-3) the neutrino survival probability may become sensitive to the V-23 octant and the sign of epsilon(tau tau). In particular, if epsilon(tau tau) greater than or similar to 10(-2) an internal I-resonance may arise independently of the matter density. For typical values found in SN simulations this takes place in the same dense-neutrino region above the neutrinosphere where collective effects occur, in particular, during the synchronization regime. This resonance may lead to an exchange of the neutrino fluxes entering the bipolar regime. The main consequences are (i) bipolar conversion taking place for normal neutrino mass hierarchy and (ii) a transformation of the flux of low-energy v(e), instead of the usual spectral swap.
Address [Esteban-Pretel, A.; Valle, J. W. F.] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, E-46071 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 1550-7998 ISBN Medium
Area (up) Expedition Conference
Notes ISI:000276195700012 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 476
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Author Fuster-Martinez, N.; Bruce, R.; Hofer, M.; Persson, T.; Redaelli, S.; Tomas, R.
Title Aperture measurements with ac dipoles and movable collimators in the Large Hadron Collider Type Journal Article
Year 2022 Publication Physical Review Accelerators and Beams Abbreviated Journal Phys. Rev. Accel. Beams
Volume 25 Issue 10 Pages 101002 - 13pp
Keywords
Abstract This paper presents a first experimental demonstration of a new nondestructive method for aperture measurements based on ac dipoles. In high intensity particle colliders, such as the CERN Large Hadron Collider (LHC), aperture measurements are crucial for a safe operation while optimizing the optics in order to reduce the size of the colliding beams and hence increase the luminosity. In the LHC, this type of measurements became mandatory during beam commissioning and the current method used is based on the destructive blowup of bunches using a transverse damper. The new method presented in this paper uses the ac-dipole excitation to generate adiabatic forced oscillations of the beam in order to create losses to identify the smallest aperture in the machine without blowing up the beam emittance. A precise and tuneable control of the oscillation amplitude enables the beams to be reused for several aperture measurements, as well as for other subsequent commissioning activities. Measurements performed with the new method are presented and compared with the current LHC transverse damper method for two different beam energies and two different operational optics.
Address [Fuster-Martinez, N.] CSIC UV, Inst Fis Corpuscular, Valencia 46908, Spain, Email: nuria.fuster@ific.uv.es
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 ISBN Medium
Area (up) Expedition Conference
Notes WOS:000875736400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5397
Permanent link to this record