摘要 :
We present in this paper the current status of searches for leptoquarks at D0. These results include the use of next leading order theoretical predictions for the cross section for pair production of leptoquarks at hadron collider...
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We present in this paper the current status of searches for leptoquarks at D0. These results include the use of next leading order theoretical predictions for the cross section for pair production of leptoquarks at hadron colliders. We also present a new optimized analysis for first generation leptoquarks with significant increase in sensitivity relative to earlier searches using DO data. The mass limits derived from this first generation leptoquark search are relevant to the recently reported high mass events at HERA.
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摘要 :
Particles with electric charge q/e (le) 10(sup (minus)3) and masses in the range 1-1000 MeV/c(sup 2) are not excluded by present experiments or by astrophysical or cosmological arguments. Such millicharged particles may be a form ...
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Particles with electric charge q/e (le) 10(sup (minus)3) and masses in the range 1-1000 MeV/c(sup 2) are not excluded by present experiments or by astrophysical or cosmological arguments. Such millicharged particles may be a form of shadow matter that couples to ordinary matter by virtue of shadow photon/photon mixing. This paper describes a search for millicharged particles in a dedicated beam-dump experiment at SLAC. A preliminary analysis of part of this data excludes particles of mass (approx)1 MeV/c(sup 2) with q/e > 6x10(sup (minus)5).
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Properties and experimental predictions of a broad class of supergravity grand unified models possessing an SU(5)-type proton decay and R parity are described. Models of this type can be described in terms of four parameters at th...
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Properties and experimental predictions of a broad class of supergravity grand unified models possessing an SU(5)-type proton decay and R parity are described. Models of this type can be described in terms of four parameters at the Gut scale in addition to those of the Standard Model i.e. m(sub 0) (universal scalar mass), m(sub 1/2) (universal gaugino mass), A(sub 0) (cubic soft breaking parameter) and tan (beta) = /. Thus the 32 SUSY masses can be expressed in terms of m(sub 0), M(sub 1/2), A(sub 0) tan (beta) and the as yet unknown t-quark mass M(sub t). Gut thresholds are examined and a simple model leads to grand unification consistent with p-decay data when 0.114 < (alpha)(sub 3)(M(sub z)) < 0.135, in agreement with current values of (alpha)(sub 3)(M(sub Z)). Proton decay is examined for the superheavy Higgs triplet mass H(sub H3) < 10M(sub G)(M(sub G) (approx equal) 1.5 (times) 10(sup 16) GeV) and squarks and gluinos lighter than 1 TeV. Throughout most of the parameter space chargino-neutralino scaling relations are predicted to hold: 2m(sub (anti Z))(sub 1) (congruent) m(sub (anti W))(sub 1) (congruent) m(sub (anti Z))(sub 2), m(sub (anti W))(sub 1) (approx equal) (1/4)m(sub (anti g)) (for (mu) > 0) or m(sub (anti W))(sub 1) (approx equal) (1/3)m(sub (anti g)) (for (mu) < 0), while m(sub (anti W))(sub 2) (congruent) m(sub (anti Z))(sub 3) (congruent) m(sub (anti Z))(sub 4) (much gt) m(sub (anti Z))(sub 1). Future proton decay experiments combined with LEP2 lead to further predictions, e.g. for the entire parameter space either proton decay should be seen at these or the (anti W)(sub 1) seen at LEP2. Relic density constraints on the (anti Z)(sub 1) further constrain the parameter space e.g. so that m(sub t) < 165 GeV, M(sub h) < 105 GeV, m(sub (anti W))(sub 1) < 100 GeV and m(sub (anti Z))(sub 1) < 50 GeV when M(sub H)(sub 3)/M(sub G) < 6.
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摘要 :
Progress is reviewed in setting mass limits for supersymmetric particles. Since missing energy is a prime signal for supersymmetry, we have calculated several sources of ''fake'' missing energy in ordinary events. The techniques f...
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Progress is reviewed in setting mass limits for supersymmetric particles. Since missing energy is a prime signal for supersymmetry, we have calculated several sources of ''fake'' missing energy in ordinary events. The techniques for finding squark-squark and gluino-gluino production are examined and constrasted for sqrt s = 0.63, 2, and 40 TeV; methods of reducing backgrounds are described. The branching ratios of scalar quarks to the lightest supersymmetric particle are calculated with full gaugino mixing. We have considered signals and backgrounds involving hard photons from photino decay and other sources. The process H implies H implies Higgsino sup 0 zino sup 0 with H implies Higgsino sup 0 implies gamma photino and zino sup 0 implies ee photino was examined in detail and found to have few backgrounds, and to provide a means of detecting a heavy Higgs particle. The direct production of charginos and neutralinos was calculated. Gluinos are considered as constituents of the proton. (ERA citation 12:014653)
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摘要 :
Comments are made on the search for supersymmetry using hadron colliders, with the intent of bringing a number of experimental aspects, specific to hadron colliders, to the attention of an audience largely composed of e exp + e ex...
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Comments are made on the search for supersymmetry using hadron colliders, with the intent of bringing a number of experimental aspects, specific to hadron colliders, to the attention of an audience largely composed of e exp + e exp - experts. A few typical processes are used to illustrate the main features. The photino is assumed to be the lightest particle with odd R-parity and scalar quarks (whatever the flavor and handedness of their partners) are assumed nearly degenerate in mass. Gluinos and scalar quarks, gauginos and scalar leptons are discussed. 48 refs., 47 figs. (ERA citation 11:012143)
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摘要 :
Present and future prospects for the discovery of new gauge bosons, Z(prime) and W(prime), are reviewed. Particular attention is paid to hadron and e(sup +)e(sup (minus)) collider searches for the W(prime) of the Left-Right Symmetric Model.
摘要 :
Present and future prospects for the discovery of new gauge bosons, Z(prime) and W(prime), are reviewed. Particular attention is paid to hadron and e(sup +)e(sup (minus)) collider searches for the W(prime) of the Left-Right Symmetric Model.
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We show that, in wide classes of supergravity models, the ratio of the leptonic and hadronic decay widths of winos is very different from that of heavy leptons which decay via the standard weak interaction. For example, it becomes...
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We show that, in wide classes of supergravity models, the ratio of the leptonic and hadronic decay widths of winos is very different from that of heavy leptons which decay via the standard weak interaction. For example, it becomes 20% in one case and 70% in another case, while it will be 36% in case of heavy leptons. The production of wino pairs in next e/sup +/e/sup -/ experiments will be tested by the ratio of leptonic and hadronic final states. (Atomindex citation 18:016968)
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