arXiv subjects

D. B. Cline

Publications and source records attributed to D. B. Cline.

31 records · Page 2Linked to original sources

arXiv2009

Constraints on Inelastic Dark Matter Signal using ZEPLIN-II Results

There has been an increasing interest on the concept of Inelastic Dark Matter (iDM) - motivated in part by some recent data. We describe the constraints on iDM from the results of the two phase dark matter detector ZEPLIN-II, which has demonstrated strong background discrimination capabilities (>98%). Using previously published estimates of the ZEPLIN-II residual background, the iDM limits presented here exclude a significantly larger iDM parameter space than the limits derived without background subtraction. Moreover, assuming standard xenon quenching factor (qXe) of 0.19, our ZEPLIN-II limits strongly suggest the exclusion of iDM signal claims at >99% C.L., for Weakly Interacting Massive Particles (WIMPs) masses >100 GeV.

astro-ph.CO↗

arXiv2007

R & D for Future Zeplin

We propose a new concept for a very low background multi-ton liquid xenon Dark Matter experiment. The detector consists of two concentric spheres and a charge readout device in the centre. Xenon between the two spheres forms a self-shield and veto device. The inner surface of the central sphere is coated with CsI to form an internal photocathode with minimum of 2πcoverage for any event in the active volume. Photoelectrons from the CsI photocathode drift toward the charge readout micro-structure in the centre of the detector. Both scintillation and ionisation are measured simultaneously for background rejection and 3-D event mapping. In addition to external shielding, the low background is achieved by eliminating PMTs and by using low radioactivity pure materials throughout the detector. We present detailed calculations of the charge readout system and design details. The detector is expected to probe the full SUSY parameter space.

astro-ph↗

arXiv2007

The Search for Primordial Black Holes Using Very Short Gamma Ray Bursts

We show the locations of the SWIFT short hard bursts (SHB) with afterglows on the galactic map and compare with the VSB BATSE events. As we have pointed out before, there is an excess of events in the galactic map of BATSE VSB events. We not that none of VSB SWIFT era events fall into this cluster. More SWIFT events are needed to check this claim. We also report a new study with KONUS data of the VSB sample with an average energy above 90 keV showing a clear excess of events below 100 ms duration (T90) that have large mean energy protons. We suggest that VSB themselves consist of two subclasses: a fraction of events have peculiar distribution properties and have no detectable counterparts, as might be expected for exotic sources such as primordial black holes. We show how GLAST could add key new information to the study of VSB bursts and could help test the black hole concept.

astro-ph↗

arXiv2007

Proposal for an Experimental Program in Neutrino Physics and Proton Decay in the Homestake Laboratory

This report is intended to describe first, the principal physics reasons for an ambitious experimental program in neutrino physics and proton decay based on construction of a series of massive water Cherenkov detectors located deep underground (4850 ft) in the Homestake Mine of the South Dakota Science and Technology Authority (SDSTA); and second, the engineering design of the underground chambers to house the Cherenkov detector modules; and third, the conceptual design of the water Cherenkov detectors themselves for this purpose. Included in this document are preliminary costs and time-to-completion estimates which have been exposed to acknowledged experts in their respective areas. We have included some contingency factors. Nevertheless, we recognize that much more extensive documentation and contingency estimates will be needed for a full technical design report. In this proposal we show the event rates and physics sensitivity for beams from both FNAL (1300 km distant from Homestake) and BNL (2540 km distant from Homestake). The program we propose will benefit from a beam from FNAL because of the high intensities currently available from the Main Injector with modest upgrades. The possibility of tuning the primary proton energy over a large range from 30 to 120 GeV also adds considerable flexibility to the program from FNAL.

hep-ex↗

arXiv2006

Comparison of VSB from BATSE, KONUS and Swift

We show the locations of the SWIFT short hard bursts (SHB) with afterglows on the Galactic map and compare with the very short bursts (VSB) BATSE events. As we have pointed out before, there is an excess of events in the Galactic map of BATSE VSB events. We note, that none of VSB SWIFT era events fall into this cluster. More SWIFT events are needed to check this claim. We also report a new study with KONUS data of the VSB sample with an average energy above 90 keV showing a clear excess of events below 100 ms duration (T_90) that have large mean energy photons. We suggest that VSB themselves consists of two subclasses: a fraction of events have peculiar distribution properties and have no detectable counter parts, as might be expected for exotic sources such as Primordial Black Holes.

astro-ph↗

arXiv2006

On the origin of bimodal duration distribution of Gamma Ray Bursts

The modified version of a bullet model for gamma ray bursts is studied. The central engine of the source produces multiple sub-jets that are contained within a cone. The emission of photons in the source frame of a sub-jet either takes part in an infinitesimally thin shell, or during its expansion for a finite time. The analysis of the observed profiles of GRBs taken by BATSE leads us to the conclusion that the latter possibility is much more favored. We also study the statistical distribution of GRBs, in the context of their bimodality of durations, taking into account the detector's capability of observing the signal above a certain flux limit. The model with shells emitting for a finite time is able to reproduce only one class of bursts, short or long, depending on the adopted physical parameters. Therefore we suggest that the GRB bimodality is intrinsically connected with two separate classes of sources.

astro-ph↗

arXiv2005

Study of Very Short GRB: New Results from BATSE and KONUS

Our recent studies of Very Short Gamma Ray Bursts (VSB) of duration T_{90} \le 100 ms have indicated a significant angular asymmetry and a uniform V/V_{max} distribution from the BATSE data. Here we update these studies, and we extend our research to events observed with KONUS satellite which gives a new insight into the spectra not possible with the BATSE data. KONUS has observed 18 events with T_{90} \le 100 ms duration. These events display considerable numbers of photons with energies above 1 MeV and have photons above 5 MeV in all cases. These appear to be some of the most energetic photons observed from any classes of GRB to date.

astro-ph↗

arXiv2005

A Concept for a Scalable 2 kTon Liquid Argon TPC Detector for Astroparticle Physics

This paper describes the results of a study on the general lines, main construction criteria, crucial points, parameters and required preliminary R&D activities for the construction of a LAr (liquid argon) imaging detector with active mass in the 10-100 kTon range. Such detectors are crucial for supernova detection, proton decay, LBL neutrino physics and other astroparticle physics applications.

astro-ph↗

arXiv2005

6D Ionization Muon Cooling with Tabletop Rings

Progress on six dimensional ionization muon cooling with relatively small rings of magnets is described. Lattices being explored include scaling sector cyclotrons with edge focusing and strong focusing, fixed field alternating gradient (FFAG) rings. Ionization cooling is provided by high pressure hydrogen gas which removes both transverse and longitudinal momentum. Lost longitudinal momentum is replaced using radio frequency (RF) cavities, giving a net transverse emittance reduction. The longer path length in the hydrogen of higher momentum muons decreases longitudinal emittance at the expense of transverse emittance. Thus emittance exchange allows these rings to cool in all six dimensions and not just transversely. Alternatively, if the RF is located after the ring, it may be possible to cool the muons by stopping them as they spiral adiabatically into a central swarm. As momentum goes to zero, the momentum spread goes to zero. The resulting cooled muons can lead to an intense muon beam which could be a source for neutrino factories or muon colliders.

physics.acc-ph↗

arXiv2001

Evidence for a Galactic Origin of Very Short Gamma Ray Bursts and Primordial Black Hole Sources

We systematically study the shortest time duration gamma ray bursts and find unique features that are best interpreted as sources of a galactic origin. There is a significant angular asymmetry and the V/Vmax distribution provides evidence for a homogenous or Euclidean source distribution. We eview the arguments that primordial black hole evaporation can give such GRBs. The rate of events is consistent with a PBH origin if we assume on enhanced local density, as are the other distributions. We suggest further tests of this hypothesis.

astro-ph↗

arXiv2000

A Neutrino-Factory Muon Storage Ring to Provide Beams for Multiple Detectors Around the World

We briefly discuss the physics motivation for a neutrino factory with varying baseline distances of about 1000 to 9000 km. We describe the amount of non planarity of the storage ring required to service three or four detectors at once. A novel bowtie storage ring is described that could in part provide these beams; a preliminary lattice design is given. We give the space angles between the various detector locations and possible sites for neutrino factories. Finally we describe detectors at the Gran Sasso Laboratory and at a new laboratory near Carlsbad, NM to observe the neutrino interactions with wrong sign leptons.

hep-ex↗

arXiv2000

The Scientific Need for a Scalar/Higgs Factory

The scalar sector of the electroweak theory can be probed by a mu^+mu^- collider S channel resonance machine. We give arguments for when such a machine may be needed and when this information could be obtained by the LHC detector. A very interesting case is the possibility that several scalar particles are in the same mass range for the supersymmetric Higgs bosons h, H, and A, which would definitely require such a machine. The Higgs factory could follow the construction of a neutrino factory.

hep-ex↗

arXiv2000

Exploring the Ultrahigh Energy Neutrino Universe

Astronomy at the highest energies observed must be performed by studying neutrinos rather than photons because the universe is opaque to photons of these energies. By making observations of neutrinos with energies above 10 EeV one can deduce information about the distribution and cosmological history of cosmic rays which may have been accelerated to energies above 100 EeV. Very large fluxes of neutrinos at these energies which exhibit a hard spectrum would be evidence of a GUT phase transition or superheavy dark matter particles. Neutrinos at energies around a PeV may be produced in observable quantities in active galaxies from the acceleration and interactions of cosmic rays in the vicinity of massive black holes or in relativistic jets produced by these black holes. Cosmological gamma-ray bursts may also produce PeV neutrinos. Neutrinos at these energies may oscillate into tau neutrinos which can travel through the Earth by the process of regeneration and produce upward moving air-showers. Neutrinos of energies above of 1000 EeV can produce ultrahigh energy cosmic rays thorugh interactions with big-bang neutrinos, producing Z bosons. This "Z-burst" phenomenon can be used to study the mass and distribution of big-bang neutrinos.

astro-ph↗