Black Hole Production at LHC: String Balls and Black Holes from pp and Lead-lead Collisions

If the fundamental planck scale is near a TeV, then parton collisions with high enough center-of-mass energy should produce black holes. The production rate for such black holes at LHC has been extensively studied for the case of a proton-proton collision. In this paper, we extend this analysis to a lead-lead collision at LHC. We find that the cross section for small black holes which may in principle be produced in such a collision is either enhanced or suppressed, depending upon the black hole mass. For example, for black holes with a mass around 3 TeV we find that the differential black hole production cross section, d\sigma/dM, in a typical lead-lead collision is up to 90 times larger than that for black holes produced in a typical proton-proton collision. We also discuss the cross-sections for `string ball' production in these collisions. For string balls of mass about 1 (2) TeV, we find that the differential production cross section in a typical lead-lead collision may be enhanced by a factor up to 3300 (850) times that of a proton-proton collision at LHC.Comment: Added some discussion, final version to appear in Phys. Rev. D (rapid communications

Control of Escherichia coli O157:H7 in large-diameter, lebanon-style bologna

Lebanon bologna raw batter was mixed with a five-strain mixture of Escherichia coli O157:H7 to achieve average inoculum levels of 7.79, 7.77, and 7.92 log CFU/g as deter mined on MSA, 202, and PRSA media, respectively. Treatment 1 consisted of a fermentation cycle of 8 hrs at an internal temperature (I.T.) of 80EF then 24 hrs at 100EF I.T., followed by 24 hrs at 110EF I.T. Treatments 2, 3, and 4 included additional heating at 115EF I.T. for 1, 2, and 5 hrs, respectively. All heat treatments resulted in product that was negative (\u3c1.9 log CFU/g detection limit) on all culture media and negative after enrichment on mEC selective medium. This study validates that a five-log reduction of E. coli O157:H7 can be achieved using the described protocol, thus meeting USDA/FSIS requirements

Characterization of a novel elliptically polarized wiggler

We report on the initial characterization of an elliptically polarized wiggler built by a collaboration between the Advanced Photon Source, the Institute of Nuclear Physics, and the National Synchrotron Light Source. The wiggler has recently been installed in the X13 straight section of the NSLS X-Ray ring. The device consists of a vertical permanent-magnet wiggler and a horizontal electromagnet wiggler. The electromagnets allow the wiggler to produce on-axis circularly polarized soft x-rays with the capability of AC modulation of the polarization. The maximum switching frequency that can be reached is 100 Hz. The degree of circular polarization of the radiation from the wiggler was characterized by making magnetic circular dichroism measurements using the X13A soft x-ray beamline. For a vertical deflection parameter, K{sub x}, of 1.6, the dichroism effects at the Fe L{sub 2,3} edges indicate a degree of circular polarization of approximately 75% using an aperture with a vertical acceptance of 87 {mu}rad. Because both the left- and right-circularly polarized photons traverse identical paths through the beamline optical system, significantly smaller intensity fluctuations associated with switching of the polarization were observed that are typically possible at bending magnet beamlines. This, together with the relatively fast modulation rate, means that it will now be feasible to perform a variety of experiments that have not been possible using bending magnet sources

Soft x-ray spectroscopy undulator beamline at the Advanced Photon Source

Construction of the high-resolution soft x ray spectroscopy undulator beamline, 2ID-C, at the Advanced Photon Source (APS) has been completed. The beamline, one of two soft x ray beamlines at the APS, will cover the photon energy range from 500 to 3,000 eV, with a maximum resolving power between 7,000 and 14,000. The optical design is based on a spherical grating monochromator (SGM) giving both high resolution and high flux throughput. Photon flux is calculated to be approximately 10{sup 12}--10{sup 13} photons per second with a beam size of approximately 1 x 1 mm{sup 2} at the sample

Status of scientific knowledge, recovery progress, and future research directions for the Gulf Sturgeon, Acipenser oxyrinchus desotoi Vladykov, 1955

The Gulf Sturgeon, Acipenser oxyrinchus desotoi, is an anadromous species of Acipenseridae and native to North America. It currently inhabits and spawns in the upper reaches of seven natal rivers along the northern coast of the Gulf of Mexico from the Suwannee River, Florida, to the Pearl River, Louisiana, during spring to autumn. Next to the Alligator Gar (Atractosteus spatula), the Gulf Sturgeon is currently the largest fish species occurring in U.S. Gulf Coast rivers, attaining a length of 2.35 m and weights exceeding 135 kg, but historically attained a substantially larger size. Historically, the spawning populations existed in additional rivers from which the species has been wholly or nearly extirpated, such as the Mobile and Ochlockonee rivers, and possibly the Rio Grande River. Most Gulf Sturgeon populations were decimated by unrestricted commercial fishing between 1895–1910. Subsequently most populations remained unrecovered or extirpated due to continued harvest until the 1970s–1980s, and the construction of dams blocking access to ancestral upriver spawning grounds. Late 20th Century harvest bans and net bans enacted by the several Gulf Coast states have stabilized several populations and enabled the Suwannee River population to rebound substantially and naturally. Hatchery supplementation has not been necessary in this regard to date. Sturgeon are resilient and adaptable fishes with a geological history of 150 million years. Research undertaken since the 1970s has addressed many aspects of Gulf Sturgeon life history, reproduction, migration, population biology, habitat requirements, and other aspects of species biology. However, many knowledge gaps remain, prominently including the life history of early developmental stages in the first year of life. Natural population recovery is evident for the Suwannee River population, but seems promising as well for at least four other populations. The Pascagoula and Pearl River populations face a challenging future due a combination of natural and anthropogenic factors. These two populations, and perhaps the Escambi River population, are particularly vulnerable to periodic mass mortality due to major stochastic events including hurricanes, flooding, hypoxia, and toxic spills. The present manuscript provides a comprehensive synthesis of knowledge regarding the Gulf Sturgeon at the organismal and population levels, identifying knowledge gaps as priorities for future research. Topics not treated in the present synthesis include morphology, internal biology, physiology, and endocrinology. Topics only briefly treated include parasites and diseases, contaminants, and sturgeon aquaculture

Control of Escherichia coli O157:H7 in large-diameter, lebanon-style bologna

Lebanon bologna raw batter was mixed with a five-strain mixture of Escherichia coli O157:H7 to achieve average inoculum levels of 7.79, 7.77, and 7.92 log CFU/g as deter mined on MSA, 202, and PRSA media, respectively. Treatment 1 consisted of a fermentation cycle of 8 hrs at an internal temperature (I.T.) of 80EF then 24 hrs at 100EF I.T., followed by 24 hrs at 110EF I.T. Treatments 2, 3, and 4 included additional heating at 115EF I.T. for 1, 2, and 5 hrs, respectively. All heat treatments resulted in product that was negative (<1.9 log CFU/g detection limit) on all culture media and negative after enrichment on mEC selective medium. This study validates that a five-log reduction of E. coli O157:H7 can be achieved using the described protocol, thus meeting USDA/FSIS requirements

Advantages of using a mirror as the first optical component for APS undulator beamlines

The advantages of using a mirror as the first optical component for an APS undulator beamline for thermal management, radiation shielding mitigation, and harmonic rejection are presented

Kaluza-Klein gravitino production with a single photon at e^+ e^- colliders

In a supersymmetric large extra dimension scenario, the production of Kaluza-Klein gravitinos accompanied by a photino at e^+ e^- colliders is studied. We assume that a bulk supersymmetry is softly broken on our brane such that the low-energy theory resembles the MSSM. Low energy supersymmetry breaking is further assumed as in GMSB, leading to sub-eV mass shift in each KK mode of the gravitino from the corresponding graviton KK mode. Since the photino decays within a detector due to its sufficiently large inclusive decay rate into a photon and a gravitino, the process e^+ e^- -> photino + gravitino yields single photon events with missing energy. Even if the total cross section can be substantial at sqrt(s)=500 GeV, the KK graviton background of e^+ e^- -> photon + graviton is kinematically advantageous and thus much larger. It is shown that the observable, sigma(e^-_L)-sigma(e^-_R), can completely eliminate the KK graviton background but retain most of the KK gravitino signal, which provides a unique and robust method to probe the supersymmetric bulk.Comment: Reference added and typos correcte

Search for Radions at LEP2

A new scalar resonance, called the radion, with couplings to fermions and bosons similar to those of the Higgs boson, is predicted in the framework of Randall-Sundrum models, proposed solutions to the hierarchy problem with one extra dimension. An important distinction between the radion and the Higgs boson is that the radion would couple directly to gluon pairs, and in particular its decay products would include a significant fraction of gluon jets. The radion had the same quantum numbers as the Standard Model (SM) Higgs boson, and therefore they can mix, with the resulting mass eigenstates having properties different from those of the SM Higgs boson. Existing searches for the Higgs boson are sensitive to the possible production and decay of radions and Higgs bosons in these models. For the first time, searches for the SM Higgs boson and flavour-independent and decay-mode independent searches for a neutral Higgs boson are used in combination to explore the parameter space of the Randall-Sundrum model. In the dataset recorded by the OPAL experiment at LEP, no evidence for radion or Higgs particle production was observed in any of those searches. The results are used to set limits on the radion and Higgs boson masses.Comment: 18 pages, 6 figures, Submitted to Phys. Lett.

Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at sqrt [ s ] = 13TeV

A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions