Physics beyond the Standard Model predicts the possible existence of new particles that can be searched at the low energy frontier in the sub-eV range. The OSQAR photon regeneration experiment looks ...for "Light Shining through a Wall" from the quantum oscillation of optical photons into "Weakly Interacting Sub-eV Particles", such as axion or Axion-Like Particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of 2 × 14.3 m. In 2014, this experiment has been run with an outstanding sensitivity, using an 18.5 W continuous wave laser emitting in the green at the single wavelength of 532 nm. No regenerated photons have been detected after the wall, pushing the limits for the existence of axions and ALPs down to an unprecedented level for such a type of laboratory experiment. The di-photon couplings of possible pseudoscalar and scalar ALPs can be constrained in the nearly massless limit to be less than 3.5·10 −8 GeV −1 and 3.2·10 −8 GeV −1 , respectively, at 95% Confidence Level.
Abstract
A Structured Laser Beam (SLB) is a type of optical beam with spatially inhomogeneous 3D polarisation structures. Generating SLBs from vector beams allows the creation of Hollow Structured ...Laser Beams (HSLB) with a dark central core. In this way, atypical electric and magnetic field vectors, which are purely longitudinally polarized in the dark zones of the beam, are obtained. The SLB spatial distribution can also include regions with both the electric and magnetic fields longitudinally polarized and oriented in the same or opposite directions. The SLB has a transverse distribution similar to that of a Bessel beam but can theoretically propagate to infinity, therefore giving the potential to generate strong, longitudinally oriented electric fields over long distances, which could possibly allow the acceleration of charged particles. The results of the study of this phenomenon, including simulations of the spatial distribution of the electromagnetic field components, are presented in this paper.
After pioneering gaseous detectors of single photon for RICH applications using CsI solid state photocathodes in MWPCs within the RD26 collaboration and by the constructions for the RICH detector of ...the COMPASS experiment at CERN SPS, in 2016 we have upgraded COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four novel photon detectors, covering a total active area of 1.5m2 have been installed in order to cope with the challenging efficiency and stability requirements of the COMPASS physics programme. They are the first application in an experiment of MPGD-based single photon detectors. All aspects of the upgrade are presented, including engineering, mass production, quality assessment and performance.
Perspectives for further developments in the field of gaseous single photon detectors are also presented.
OSQAR chameleon afterglow search experiment Sulc, M.; Pugnat, P.; Ballou, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Odprti dostop
OSQAR experiment has been extended to the quest of chameleon particles with environment-dependent mass from the search of a magnetic afterglow effect. OSQAR-CHASE (chameleon afterglow search) has ...been run in 2017 using one spare LHC dipole providing a 9 T transverse magnetic field with an 18.5 W laser and state-of-the art CCD detector. Experimental results with and without magnetic field were preliminary analyzed and no clear evidence for a photon-coupled chameleons was confirmed. The very weak false signals was observed with decay time 4300 s. It can be explained by decrease of dark current from initial higher values during CCD cooling in detection phase. Increasing of the sensitivity of the OSQAR-CHASE experiment over the previous GammeV reference experiment assumes that the present coupling constant limit can be reduced around factor of 4.
•OSQAR laser experiment at CERN has been extended to the quest of chameleon particles.•The 18 W laser was shining through a 9 T magnetic field of spare LHC dipole.•The very weak 4.3 Hz false signals was observed after laser switch-off.•There was no difference in afterglow optical signal with and without magnetic field.•The present chameleon–photon coupling constant limit can be reduced by factor of 4.
Measurement of forage mass is critical to the management of forage allowance in grazing systems. The rising plate meter (RPM) was developed to monitor forage mass quickly and easily; however, it must ...be calibrated to provide reliable calculations of forage mass and the calibration coefficients may vary across seasons. Our objective was to investigate seasonal patterns in calibrations of the RPM for estimating forage mass in six cool-season grass swards in Ohio. The RPM reading was highly significant (P < 0.01) in explaining variation in forage mass across sites and weeks; however, the RPM × week, RPM × site, and RPM × week × site interactions (P < 0.01) for forage mass indicated the relationship between RPM reading and forage mass varied among sites and over time. At one site, the RPM to forage mass relationship was investigated for three cool-season grass species, but the RPM × species and RPM × week × species interactions were not significant (P > 0.05). Although there was variation among and within sites for the slope coefficients of forage mass regressed on RPM reading, a broadly similar seasonal pattern was found at most sites. The slope coefficients were usually high in early spring, decreased rapidly during the first weeks of the growing season, and then increased from early summer to the autumn. We concluded the RPM should be calibrated at least monthly over the growing season to define the seasonal pattern and changes in the slope coefficients for forage mass regressed on RPM readings.
Recent theoretical and experimental studies highlight the possibility of new fundamental particle physics beyond the Standard Model that can be probed by sub-eV energy experiments. The OSQAR photon ...regeneration experiment looks for “Light Shining through a Wall” from the quantum oscillation of optical photons into “Weakly Interacting Sub-eV Particles”, like axion or axion-like particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of
2
×
14.3
m. No excess of events has been detected over the background. The di-photon couplings of possible new light scalar and pseudo-scalar particles can be constrained in the massless limit to be less than
8.0
×
10
-
8
GeV
-
1
. These results are very close to the most stringent laboratory constraints obtained for the coupling of ALPs to two photons. Plans for further improving the sensitivity of the OSQAR experiment are presented.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In 2016 we have upgraded the COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four new photon detectors, covering a total active area of 1.5
m
2
, have been installed in order ...to cope with the challenging efficiency and stability requirements of the COMPASS physics programme. The new detector architecture consists in a hybrid MPGD combination: two layers of THGEMs, the first of which also acts as a reflective photocathode thanks to CsI coating, are coupled to a bulk Micromegas on a pad-segmented anode. These detectors are the first application in an experiment of MPGD-based single photon detectors. Presently, we are further developing the MPGD-based PDs to make them adequate for a setup at the future EIC collider. All aspects of the COMPASS RICH-1 Photon Detectors upgrade are presented: R&D, engineering, mass production, QA and performance; the on-going development for collider application is also presented.
Damage to spermatozoa during cryopreservation is regarded as a major obstacle to the expansion of sperm storage technology. The authors used two-dimensional polyacrylamide gel electrophoresis and ...matrix-associated laser desorption/ionization time-of-flight mass spectrometry to explore whether the protein profile of common carp (
Cyprinus carpio) spermatozoa is affected by cryopreservation. Fourteen protein spots were significantly altered following cryopreservation. Eleven of these were identified: three as specific membrane proteins (N-ethylmaleimide-sensitive fusion protein attachment protein alpha, cofilin 2, and annexin A4) involved in membrane trafficking, organization, and cell movement; six as cytoplasmic enzymes (S-Adenosylhomocysteine hydrolase, Si:dkey-180p18.9 protein, lactate dehydrogenase B, phosphoglycerate kinase 1, transaldolase 1, and esterase D/formylglutathione hydrolase) involved in cell metabolism, oxidoreductase activity, and signal transduction; and two as transferrin variant C and F. Based on these findings, the authors hypothesize that transferrin in cryopreserved sperm may protect spermatozoa against oxidative damage during the freeze-thaw process. Cryopreservation caused changes in spermatozoa protein profiles that may lead to decreased spermatozoa velocity, motility, and fertilization success, and to subsequent ova hatching rate.
The effect of cryopreservation on the protein phosphorylation/dephosphorylation pattern of common carp (Cyprinus carpio) sperm is described. Sperm was diluted in dimethyl sulfoxide (DMSO) and ...ethylene glycol (EG)-based extenders, followed by equilibration, freezing, and thawing. Proteins extracted from fresh and cryopreserved spermatozoa were separated on SDS-PAGE and two-dimensional gel electrophoresis, blotted on polyvinylidene difluoride membrane, and treated with anti-phosphotyrosine, anti-phosphothreonine, or anti-phosphoserine antibodies. For the subsequent protein identification we used matrix-associated laser desorption/ionization time-of-flight mass spectrometry. The results demonstrated that cryopreservation with either DMSO or EG extender significantly altered the phosphorylation state of sperm proteins on tyrosine or threonine residues. A dramatic decrease in tyrosine phosphorylation was detected in the cryopreservation procedures with DMSO extender. Endoplasmin, transketolase, and S-adenosylhomocysteine hydrolase were identified as proteins that play a key role in cellular stress responses and oxidation and/or reduction reactions. Results indicate that the phosphorylation and/or dephosphorylation modifications of sperm proteins that occur during cryopreservation could stimulate a series of biochemical effects interfering with spermatozoa function and leading to a loss of motility and fertilization ability. Our findings indicated that use of EG extender provided superior protein preservation during sperm storage.
We are developing large size THick GEM (THGEM)-based detectors of single photons, mainly meant for Cherenkov imaging applications. The R&D programme includes the complete characterisation of the ...THGEM electron multipliers, the study of the aspects related to the detection of single photons and the engineering towards large size detector prototypes. Our most recent achievements include dedicated studies concerning the ion backflow to the photocathode; relevant progress in the engineering aspects, in particularly related to the production of large-size THGEMs, where the strict correlation between the local gain-value and the local thickness-value has been demonstrated and a 300300 mm super(2) active area detector has been successfully operated at the CERN PS T10 test beam; the introduction of a new hybrid detector architecture, offering promising performance, which is formed by a THGEM layer which acts both as photocathode and pre-amplification device, followed by a MICROMEGAS (MM) multiplication stage. We report about the general status of the R&D programme and, in detail, about the recent progress.
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