Spin effects at supercollider energies

Bourrely, Claude; Soffer, Jacques; Renard, F.M.; Taxil, P.

doi:10.1016/0370-1573(89)90081-1

Cited by 85 publications

(88 citation statements)

References 140 publications

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“…These are: the the BergerQiu parameterization [8] ∆g(x) = g(x) (x > x c ), ∆g(x) = x xc g(x) (x < x c ), where x c ∼ 0.2 yields a value of ∆g ∼ 2.5 at Q 2 = 10 GeV 2 , case (4); and the rather modest ∆g(x) proposal of Ref. [9], with ∆g ∼ 0.2 at Q 2 = 10 GeV 2 , case (5). Quark distributions can be chosen, in association with all the ∆g(x) forms adopted in the above five cases, that reproduce the normal deep inelastic data and the polarized proton EMC data.…”

mentioning

confidence: 99%

Gluon Fusion: A Probe of Higgs SectorCPViolation

Gunion¹,

Yuan²,

Grza̧dkowski³

1993

Phys. Rev. Lett.

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We demonstrate that CP violation in the Higgs sector, e.g. of a multi-doublet model, can be directly probed using gluon-gluon collisions at the SSC.Understanding the Higgs sector is one of the fundamental missions of future high energy colliders such as the SSC and LHC. In particular, it will be important to know if CP violation is present in the Higgs sector. Generally, either spontaneous or explicit CP violation can be present if the Higgs sector consists of more than the single doublet field of the Standard Model (SM). (For a review of this and other issues summarized below, see Ref.[1], and references therein.) However, important classes of models with extended Higgs sectors either do not allow for Higgs sector CP violation or are inconsistent with current experiment if significant CP violation in the Higgs sector is present. Among such models, supersymmetric theories are the most important example. There, a phase for a Higgs field vacuum expectation value in excess of about 10 −2 would imply imaginary components for slepton, squark, chargino and neutralino propagators that would result in electric dipole moments of the electron and neutron in excess of experimental limits. Thus, once a Higgs boson is discovered, it will be crucial to determine whether or not it is a pure CP eigenstate.Although there are a variety of experimental observables that are indirectly sensitive to CP violation in the Higgs sector (such as EDM's, top quark production and decay distributions, etc.), CP-violating contributions typically first appear at one-loop, or are otherwise suppressed, and will be very difficult to detect in a realistic experimental environment. In addition, if CP violation in this class of observables is detected, it could easily arise from sources other than the Higgs sector. In this letter, we shall show that the CP nature of a neutral Higgs boson (φ) is directly probed by the difference between its production rates through gluon-gluon fusion processes for colliding proton beams of opposite polarizations. (The proposed asymmetry is closely analogous to that developed previously for collisions of polarized back scattered laser beams at a future linear e + e − collider.[2] ) We compute the ⋆

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confidence: 99%

Gluon Fusion: A Probe of Higgs SectorCPViolation

Gunion¹,

Yuan²,

Grza̧dkowski³

1993

Phys. Rev. Lett.

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“…The first one (BSRT) uses polarized parton densities as given in ref. [ 6] and unpolarized densities of ref. [ 18], the latter being compatible with those; the second one (AS) is based on polarized densities of ref.…”

Section: The Left-right Asymmetrymentioning

confidence: 99%

“…An option with polarized proton beams is very seriously considered at RHIC with JS = 50-500 Ge V and IE= 2 X 10 32 cm 2 s -I [ 3,2] and various theoretical studies have been performed recently for example on spin asymmetries in jet or direct photon production [ 4]. Concerning the very high energy domain which is relevant at LHC and SSC, besides dedicated workshops [ 2,5], an extensive survey of the phenomenology ofthe spin effects at the future supercolliders has been performed [ 6] and it was found that large and meaningful spin asymmetries can be expected both according to the standard model and to various scenarios of new physics. In particular the interest of polarized beams in order to study the origin of new neutral gauge bosons has been recently emphasized [ 7].…”

Section: Introductionmentioning

confidence: 99%

“…Hopefully, forthcoming deep inelastic scattering experiments with a polarized lepton beam on a polarized proton or deuteron target and future results from polarized RHIC should improve our knowledge [ 12 ]. In fact, it can be advocated [ 6,13] that at the supercolliders themselves, with polarized beams, the asymmetries for the very copious, well known standard electroweak processes would allow to perform a "calibration" of the spindependent partonic distributions.…”

Section: Introductionmentioning

confidence: 99%

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Beam polarization at LHC and SSC. Expected asymmetries in the Bess model and comparison with other models

Casallbuoni

Chiappetta²,

Deandrea

et al. 1992

Physics Letters B

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In view of recent and foreseen technical advances in beam polarization in future proton colliders we discuss possible tests of non-standard physics at LHC and SSC assuming initial proton polarization, specifically to test for a strong electroweak sector and comparing with different extended gauge models. We examine lepton pair production, studying left-right and forward-backward asymmetries, assuming quark-antiquark and WW fusion production mechnisms. We discuss the uncertainties related to polarized proton structure functions.

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“…[12]. We adopt the Glück, Reya, and Vogt (GRV) leading order unpolarized parametrization for the nucleon parton distributions [13].…”

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confidence: 99%

Particle–antiparticle asymmetries of Λ production in hadron–nucleon collisions

Schmidt

Yang

2004

Physics Letters B

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The particle-antiparticle asymmetries of Λ production in 250 GeV/c π ± , K ± , and p -nucleon collisions are studied with two model parametrizations of quark to Λ fragmentation functions. It is shown that the available data can be qualitatively explained by the calculated results in both the quark-diquark model and a pQCD based analysis of fragmentation functions. The differences in the two model predictions are significant for K ± beams, and high precision measurements of the asymmetries with detailed x F and P T information can discriminate between different predictions.

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Spin effects at supercollider energies

Cited by 85 publications

References 140 publications

Gluon Fusion: A Probe of Higgs SectorCPViolation

Gluon Fusion: A Probe of Higgs SectorCPViolation

Beam polarization at LHC and SSC. Expected asymmetries in the Bess model and comparison with other models

Particle–antiparticle asymmetries of Λ production in hadron–nucleon collisions

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