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Title: Discovering supersymmetry with m{sub 0}{sup 2}<0 in the first CERN LHC physics run

Abstract

In minimal supergravity, the parameter space where the slepton is the lightest superpartner is usually neglected, because of strong constraints on charged dark matter. When the gravitino is the true lightest superpartner, this region avoids these constraints and offers spectacular collider signals. We investigate this scenario for the Large Hadron Collider and find that a large portion of the ignored minimal supergravity parameter space can lead to discovery within the first physics run, with 1-4 fb{sup -1} of data. We find that there are regions where discovery is feasible with only 1 d of running.

Authors:
;  [1]
  1. Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)
Publication Date:
OSTI Identifier:
20929577
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevD.75.115015; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CERN LHC; MATHEMATICAL SPACE; NONLUMINOUS MATTER; SIGNALS; SUPERGRAVITY; SUPERSYMMETRY

Citation Formats

Rajaraman, Arvind, and Smith, Bryan T. Discovering supersymmetry with m{sub 0}{sup 2}<0 in the first CERN LHC physics run. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.115015.
Rajaraman, Arvind, & Smith, Bryan T. Discovering supersymmetry with m{sub 0}{sup 2}<0 in the first CERN LHC physics run. United States. doi:10.1103/PHYSREVD.75.115015.
Rajaraman, Arvind, and Smith, Bryan T. Fri . "Discovering supersymmetry with m{sub 0}{sup 2}<0 in the first CERN LHC physics run". United States. doi:10.1103/PHYSREVD.75.115015.
@article{osti_20929577,
title = {Discovering supersymmetry with m{sub 0}{sup 2}<0 in the first CERN LHC physics run},
author = {Rajaraman, Arvind and Smith, Bryan T.},
abstractNote = {In minimal supergravity, the parameter space where the slepton is the lightest superpartner is usually neglected, because of strong constraints on charged dark matter. When the gravitino is the true lightest superpartner, this region avoids these constraints and offers spectacular collider signals. We investigate this scenario for the Large Hadron Collider and find that a large portion of the ignored minimal supergravity parameter space can lead to discovery within the first physics run, with 1-4 fb{sup -1} of data. We find that there are regions where discovery is feasible with only 1 d of running.},
doi = {10.1103/PHYSREVD.75.115015},
journal = {Physical Review. D, Particles Fields},
number = 11,
volume = 75,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}
  • Series of compositions Bi{sub 2}(M'{sub x}M{sub 1-x}){sub 4}O{sub 9} with x=0.0, 0.1,..., 1.0 and M'/M=Ga/Al, Fe/Al and Fe/Ga were synthesized by dissolving appropriate amounts of corresponding metal nitrate hydrates in glycerine, followed by gelation, calcination and final heating at 800 {sup o}C for 24 h. The new compositions with M'/M=Ga/Al form solid-solution series, which are isotypes to the two other series M'/M=Fe/Al and Fe/Ga. The XRD data analysis yielded in all cases a linear dependence of the lattice parameters related on x. Rietveld structure refinements of the XRD patterns of the new compounds, Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} revealmore » a preferential occupation of Ga in tetrahedral site (4 h). The IR absorption spectra measured between 50 and 4000 cm{sup -1} of all systems show systematic shifts in peak positions related to the degree of substitution. Samples treated in {sup 18}O{sub 2} atmosphere (16 h at 800 {sup o}C, 200 mbar, 95% {sup 18}O{sub 2}) for {sup 18}O/{sup 16}O isotope exchange experiments show a well-separated IR absorption peak related to the M-{sup 18}O{sub c}-M vibration, where O{sub c} denotes the common oxygen of two tetrahedral type MO{sub 4} units. The intensity ratio of M-{sup 18}O{sub c}/M-{sup 16}O{sub c} IR absorption peaks and the average crystal sizes were used to estimate the tracer diffusion coefficients of polycrystalline Bi{sub 2}Al{sub 4}O{sub 9} (D=2x10{sup -22} m{sup 2}s{sup -1}), Bi{sub 2}Fe{sub 4}O{sub 9} (D=5x10{sup -21} m{sup 2}s{sup -1}), Bi{sub 2}(Ga/Al){sub 4}O{sub 9} (D=2x10{sup -21} m{sup 2}s{sup -1}) and Bi{sub 2}Ga{sub 4}O{sub 9} (D=2x10{sup -20} m{sup 2}s{sup -1}). - Graphical abstract: Fig. Perspective view of the mullite-type Bi{sub 2}(M'{sub x}M{sub 1-x}){sub 4}O{sub 9} unit cell (M', M=Al, Ga, Fe). Display Omitted« less
  • {sup 151}Eu-Moessbauer spectroscopic and powder X-ray diffraction (XRD) study has been performed for the Eu {sub y}M{sub 1-y}O{sub 2-x} (M = Th and U) systems over the entire composition range of 0 {<=} y {<=} 1.0. The XRD results of the Eu-Th system showed that a very wide defect-fluorite (DF) type phase in which oxygen vacancies (V {sub O}) are disordered (x = y/2) is formed for 0 {<=} y < 0.5 and that two-phase regions sandwitching a narrow C-type (C) single phase around y {approx} 0.8 appear for 0.5 < y < 0.8 (DF + C) and 0.82 <more » y < 1.0 (C + B-type (monoclinic) Eu{sub 2}O{sub 3}). The Moessbauer results show that the isomer shifts (ISs) of Eu{sup 3+} in this system smoothly increase with Eu composition, y. The decrease of average coordination number (CN) of O{sup 2-} around Eu{sup 3+} with increasing y (CN = 8 - 2y) (x = y/2) results in the decrease of the average Eu-O bond length, which is due to the decrease of repulsion force between O{sup 2-} anions. This result confirms that the IS of Eu{sup 3+} correlates well with the average Eu-O bond length in oxide systems. For the Eu-U system, the lattice parameter, a {sub 0}, of the system decreases almost linearly with y, in accordance with the calculated a {sub 0} versus y curve for the oxygen-stoichiometric (i.e. x = 0) fluorite-type dioxide (CN = 8). The ISs of Eu{sup 3+} in this composition range remain almost constant around 0.5 mm/s, which is comparable to those of pyrochlore oxides (Eu{sub 2}Zr{sub 2}O{sub 7} and Eu{sub 2}Hf{sub 2}O{sub 7} (y = 0.5)) with O{sup 2-}-eight-fold coordinated Eu{sup 3+}(CN = 8)« less
  • A search for the decays [ital K][sup +][r arrow][pi][sup +][nu][bar [nu]] and [ital K][sup +][r arrow][pi][sup +][ital X0], where [ital X][sup 0] is any weakly interacting neutral particle or system of neutral particles with 150[lt][ital M][sub [ital X]][sup 0][lt]250 MeV/[ital c][sup 2], was performed in the pion kinematic region below the [ital K][sub [pi]2]([ital K][sup +][r arrow][pi][sup +][pi][sup 0]) peak. An upper limit on [ital B]([ital K][sup +][r arrow][pi][sup +][nu][bar [nu]]) is set at 1.7[times]10[sup [minus]8] (90% C.L.) and [ital B]([ital K][sup +][r arrow][pi][sup +][ital X0]) is restricted to the 10[sup [minus]7] level or lower. Limits are also set formore » the production of [ital K][sup +][r arrow][pi][sup +][nu][bar [nu]] through scalar or tensor interactions at 1.8[times]10[sup [minus]8] and 1.0[times]10[sup [minus]8] (90% C.L.), respectively.« less
  • The role of B{sub 2}O{sub 3} in realizing the long phosphorescence of Eu(II)+Dy(III) doped strontium aluminates has been investigated. IR and solid state {sup 27}Al MAS NMR spectra show the incorporation of boron as BO{sub 4} in the AlO{sub 4} framework of SrAl{sub 2}O{sub 4} and Sr{sub 4}Al{sub 14}O{sub 25}. Phosphor, made free of glassy phases by washing with hot acetic acid+glycerol, did not show any photoconductivity under UV irradiation, indicating that the mechanism involving hole conduction in valence band is untenable for long phosphorescence. EPR studies confirm the presence of both electron and hole trap centers. Dy{sup 3+} formsmore » substitutional defect complex with borate; [Dy-BO{sub 4}-V{sub Sr}]{sup 2-}, and acts as a hole trap center. The electron centers are formed by the oxygen vacancies associated with BO{sub 3}{sup 3-}, i.e. [BO{sub 3}-V{sub O}]{sup 3-}. Under indigo light or near UV irradiation, the photoinduced electron centers are formed as [BO{sub 3}-V{sub O}(e')]{sup 4-}. The holes are released from [Dy-BO{sub 4}-V{sub Sr}(h{center_dot})]{sup 1-} under thermal excitation at room temperature. The recombination of electrons with holes releases energy which is expended to excite Eu{sup 2+} to induce long phosphorescence.« less
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