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R. Shanidze

Publications and source records attributed to R. Shanidze.

13 recordsLinked to original sources
arXiv2019

Letter of Interest for a Neutrino Beam from Protvino to KM3NeT/ORCA

The Protvino accelerator facility located in the Moscow region, Russia, is in a good position to offer a rich experimental research program in the field of neutrino physics. Of particular interest is the possibility to direct a neutrino beam from Protvino towards the KM3NeT/ORCA detector, which is currently under construction in the Mediterranean Sea 40 km offshore Toulon, France. This proposal is known as P2O. Thanks to its baseline of 2595 km, this experiment would yield an unparalleled sensitivity to matter effects in the Earth, allowing for the determination of the neutrino mass ordering with a high level of certainty after only a few years of running at a modest beam intensity of $\approx$ 90 kW. With a prolonged exposure ($\approx$ 1500 kW*yr), a 2$σ$ sensitivity to the leptonic CP-violating Dirac phase can be achieved. A second stage of the experiment, comprising a further intensity upgrade of the accelerator complex and a densified version of the ORCA detector (Super-ORCA), would allow for up to a 6$σ$ sensitivity to CP violation and a 10$^\circ$-17$^\circ$ resolution on the CP phase after 10 years of running with a 450 kW beam, competitive with other planned experiments. The initial composition and energy spectrum of the neutrino beam would need to be monitored by a near detector, to be constructed several hundred meters downstream from the proton beam target. The same neutrino beam and near detector set-up would also allow for neutrino-nucleus cross section measurements to be performed. A short-baseline sterile neutrino search experiment would also be possible.

physics.ins-det↗
arXiv2007

Sensitivity studies for the cubic-kilometre deep-sea neutrino telescope KM3NeT

The observation of high-energy neutrinos from astrophysical sources would substantially improve our knowledge and understanding of the non-thermal processes in these sources, and would in particular pinpoint the accelerators of cosmic rays. The sensitivity of different design options for a future cubic-kilometre scale neutrino telescope in the Mediterranean Sea is investigated for generic point sources and in particular for some of the galactic objects from which TeV gamma emmission has recently been observed by the H.E.S.S. atmospheric Cherenkov telescope. The effect of atmospheric background on the source detection probabilities has been taken into account through full simulation. The estimated event rates are compared to previous results and limits from present neutrino telescopes.

astro-ph↗
arXiv2002

Deeply-Virtual Compton Scattering on Deuterium and Neon at HERMES

We report the first observation of azimuthal beam-spin asymmetries in hard electroproduction of real photons off nuclei. Attributed to the interference between the Bethe-Heitler process and the deeply-virtual Compton scattering process, the asymmetry gives access to the latter at the amplitude level. This process appears to be the theoretically cleanest way to access generalized parton distributions. The data presented here have been accumulated by the HERMES experiment at DESY, scattering the HERA 27.6 GeV positron beam off deuterium and neon gas targets.

hep-ex↗
arXiv2000

Measuring the Higgs Branching Fraction into two Photons at Future Linear \ee Colliders

We examine the prospects for measuring the \gaga branching fraction of a Standard Model-like Higgs boson with a mass of 120 GeV at the future TESLA linear \ee collider, assuming an integrated luminosity of 1 ab$^{-1}$ and center-of-mass energies of 350 GeV and 500 GeV. The Higgs boson is produced in association with a fermion pair via the Higgsstrahlung process \ee $\to ZH$, with $Z \to$ \qq or \nn, or the WW fusion reaction $e^+e^- \to ν_e \bar{ν_e} H$. A relative uncertainty on BF(\hgg) of~16% can be achieved in unpolarized \ee collisions at $\sqrt{s}$=~500 GeV, while for $\sqrt{s}$=~350 GeV the expected precision is slightly poorer. With appropriate initial state polarizations $Δ$BF(\hgg)/BF(\hgg) can be improved to 10%. If this measurement is combined with the expected error for the total Higgs width, a precision of 10% on the \gaga Higgs boson partial width appears feasible.

hep-ph↗
arXiv1999

Measurements of the radiation hardness of selected scintillating and light guide fiber materials

Radiation hardness studies of KURARAY SCSF-78M scintillating fibers and clear fibers from KURARAY and pol.hi.tech. performed under different dose rate conditions in proton and electron beams are summarized. For high dose rates in-situ measurements of the fiber light output were done. During several months after irradiation all fibers were measured concerning light emission and transparency. Fibers irradiated at high rates to about 1 Mrad are clearly damaged but recover within a few hours up to several weeks. Using smaller rates up to the same integral dose a decrease of the light output of scintillating fibers of up to 30% can not be excluded. Clear fibers seem to be uneffected up to 400 krad. No significant influence of fiber coverage and atmosphere during irradiation was found.

physics.ins-det↗
arXiv1999

A Fiber Detector Radiation Hardness Test

An intense 146 MeV/c pion beam was stopped inside a scintillating fiber detector made out of 12 planes with 16 pixels each, where every pixel consists out of 8 times 8 scintillating fibers of 500 mkm diameter dense packed. The detector was irradiated for 52 hours to more than 1 Mrad at its center. Before and directly after the irradiation the detector has been exposed to a particle beam to compare the corresponding light output. This study was continued during the following three months using cosmic rays. No damage was found taking into account the measurement errors of 5-10 %. In contrast a 9 cm deep lucite degrader became irreversibly non-transparent in the irradiation region.

physics.ins-det↗
arXiv1998

Testrun results from prototype fiber detectors for high rate particle tracking

A fiber detector concept has been realized allowing to registrate particles within less than 100 nsec with a space point precision of about 0.1 mm at low occupancy. Three full size prototypes have been build by different producers and tested at a 3 GeV electron beam at DESY. After 3 m of light guides 8-10 photoelectrons were registrated by multichannel photomultipliers providing an efficiency of more than 99%. Using all available data a resolution of 0.086 mm was measured.

physics.ins-det↗
arXiv1998

Tests of a fiber detector concept for high rate particle tracking

A fiber detector concept is suggested allowing to registrate particles within less than 100 nsec with a space point precision of about 0.1 mm at low occuppancy. The fibers should be radiation hard for 1 Mrad/year. Corresponding prototypes have been build and tested at a 3 GeV electron beam at DESY. Preliminary results of these tests indicate that the design goal for the detector is reached.

physics.ins-det↗
arXiv1998

Fiber technology applications for a future e+e- linear collider detector

The advantages and possibilities of fiber technology for the detection of particles in 500 GeV e+e- reactions are considered. It is suggested to build a fast trigger which could be used also for intermediate tracking. A fiber preshower in front of the electromagnetic calorimeter would allow to identify electrons and photons with a space precision better than 0.1 mm.

physics.ins-det↗
arXiv1997

Development of scintillating fiber detector technology for high rate particle tracking

The performance of a scintillating fiber detector prototype for tracking under high rate conditions is investigated. A spatial resolution of about100 micron is aimed for the detector. Further demands are low occupancy and radiation hardness up to 1 Mrad/year. Fibers with different radii and different wavelengths of the scintillation light from different producers have been extensively tested concerning light output, attenuation length and radiation hardness, with and without coupling them to light guides of different length and diameter. In a testrun at a 3 GeV electron beam the space dependent efficiency and spatial resolution of fiber bundels were measured by means of two external reference detectors with a precision of 50 micron. The light output profile across fiber roads has been determined with the same accuracy. Different technologies were adopted for the construction of tracker modules consisting of 14 layers of 0.5 mm fibers and 0.7 mm pitch. A winding technology provides reliable results to produce later fiber modules of about 25 cm x 25 cm area. We conclude that on the basis of these results a fiber tracker for high rate conditions can be built.

hep-ex↗
arXiv1996

Bound States of Two Gluinos at the Tevatron and LHC

We calculate the production cross-sections for the vector and pseudoscalar bound states of two gluinos. It is shown that existing and future colliders imply a realistic chance of observing gluinonium as a narrow peak in the two-jet invariant mass spectrum. With an integrated luminosity of 0.2 fb$^{-1}$ at the Tevatron, and the high efficiency for tagging heavy quark jets at CDF, one should be able to detect vector gluinonium for gluino masses up to about 170 GeV; or up to about 260 GeV for an upgraded Tevatron with a centre of mass energy of 2 TeV and an integrated luminosity of 1 fb$^{-1}$. The significantly higher energy and luminosity of LHC should allow pseudoscalar gluinonium to be detected for gluino masses up to about 1500 GeV for an assumed luminosity of 200 fb$^{-1}$. These results are insensitive to the details of supersymmetry models, provided that R-parity is conserved and the gluinos are lighter than the squarks. In addition, gluinonium detection implies a relatively accurate measure of the gluino mass, which is difficult to determine by other means.

hep-ph↗
arXiv1995

On $Z$ and $Z + jet$ Production in Heavy Ion Collisions

Z+jet production in heavy ion collisions at the LHC is proposed as a possible probe of the properties of the dense hadronic matter. It is shown that the accuracy of this measurement with general purpose LHC detectors and under realistic experimental conditions can be high enough. It is argued also that $Z$-boson production and subsequent leptonic decay is a good reference process for this measurement, as well as for the QCD process of high $P_T$ jet pair production.

hep-ph↗