Pion Absorption in Nuclei

Ashery, D.; Schiffer, J. P.

doi:10.1146/annurev.ns.36.120186.001231

Cited by 141 publications

(56 citation statements)

References 76 publications

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“…The proton sample contains background protons knocked out from the beam pipe and the detector materials by interactions of produced hadrons in these materials [43]. Most of these protons have large d ca and are not reconstructed as primary particles.…”

Section: E Proton Background Correctionmentioning

confidence: 99%

Systematic measurements of identified particle spectra inpp,d+Au, andAu
Abelev¹,
Aggarwal²,
Ahammed³
et al. 2009
Phys. Rev. C
906
69
905
6
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Identified charged-particle spectra of π ± , K ± , p, and p at midrapidity (|y| < 0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d + Au collisions at √ s NN = 200 GeV and for Au + Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm 3 for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au + Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly 034909-2 SYSTEMATIC MEASUREMENTS OF IDENTIFIED . . . (2009) with centrality in peripheral Au + Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close to the predicted phase-transition temperature, suggesting that chemical freeze-out happens in the vicinity of hadronization and the chemical freeze-out temperature is universal despite the vastly different initial conditions in the collision systems. The extracted kinetic freeze-out temperature, while similar to the chemical freeze-out temperature in pp, d + Au, and peripheral Au + Au collisions, drops significantly with centrality in Au + Au collisions, whereas the extracted transverse radial flow velocity increases rapidly with centrality. There appears to be a prolonged period of particle elastic scatterings from chemical to kinetic freeze-out in central Au + Au collisions. The bulk properties extracted at chemical and kinetic freeze-out are observed to evolve smoothly over the measured energy range, collision systems, and collision centralities. PHYSICAL REVIEW C 79, 034909

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Section: E Proton Background Correctionmentioning

confidence: 99%

Systematic measurements of identified particle spectra inpp,d+Au, andAu
Abelev¹,
Aggarwal²,
Ahammed³
et al. 2009
Phys. Rev. C
906
69
905
6
View full text Add to dashboard Cite

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“…This has been verified in the case of diffractive dissociation of a high energy pion into dijets πA → qqA ′ in which the nucleus is left in its ground state [99]. When the hadronic jets have balancing but high transverse momentum, one studies the small size fluctuation of the incident pion.…”

Section: Other Qcd Phenomenology Related To Lightfront Wavefunctionsmentioning

confidence: 84%

New Results in Light-Front Phenomenology

Brodsky¹

2004

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The light-front quantization of gauge theories in light-cone gauge provides a frameindependent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitarity, and a trivial vacuum. In this talk I review the theoretical methods and constraints which can be used to determine these central elements of QCD phenomenology. The freedom to choose the light-like quantization four-vector provides an explicitly covariant formulation of light-front quantization and can be used to determine the analytic structure of light-front wave functions and define a kinematical definition of angular momentum. The AdS/CFT correspondence of large N C supergravity theory in higher-dimensional anti-de Sitter space with supersymmetric QCD in 4-dimensional space-time has interesting implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for exclusive processes. String/gauge duality also predicts the QCD power-law behavior of light-front Fock-state hadronic wavefunctions with arbitrary orbital angular momentum at high momentum transfer. The form of these nearconformal wavefunctions can be used as an initial ansatz for a variational treatment of the light-front QCD Hamiltonian. The light-front Fock-state wavefunctions encode the bound state properties of hadrons in terms of their quark and gluon degrees of freedom at the amplitude level. The nonperturbative Fock state wavefunctions contain intrinsic gluons, and sea quarks at any scale Q with asymmetries such as s(x) =s(x),ū(x) =d(x). Intrinsic charm and bottom quarks appear at large x in the light-front wavefunctions since this minimizes the invariant mass and off-shellness of the higher Fock state. In the case of nuclei, the Fock state expansion contains "hidden color" states which cannot be classified in terms of nucleonic degrees of freedom. I also briefly review recent analyses which shows that some leading-twist phenomena such as the diffractive component of deep inelastic scattering, single-spin asymmetries, nuclear shadowing and antishadowing cannot be computed from the LFWFs of hadrons in isolation.2

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“…Some simplifying assumptions concerning this interactions have been made. Both for pions and protons, the knock-out interaction has been considered separately, using the data from [17,20,21] for pions, and from [12] for protons, respectively. The rest of the channels have been considered as equivalent to the interaction on an effective number of nucleons.…”

Section: Model Calculations For the Degradationmentioning

confidence: 99%

Comparative energy dependence of proton and pion degradation in diamond

Lazanu

1999

Nuclear Instruments and Methods in Physics Research Section A:

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A comparative theoretical study of the damages produced by protons and pions, in the energy range 50 MeV ÷ 50 GeV, in diamond, is presented. The concentration of primary defects (CPD) induced by hadron irradiation is used to describe material degradation. The CPD has very different behaviours for protons and pions: the proton degradation is important at low energies and is higher than the pion one in the whole energy range investigated, with the exception of the ∆ 33 resonance region, where a large maximum of the degradation exists for pions.In comparison with silicon, the most investigated and the most utilised semiconductor material for detectors, diamond theoretically proves to be one order of magnitude more resistant both to proton and to pion irradiation.

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Pion Absorption in Nuclei

Cited by 141 publications

References 76 publications

Systematic measurements of identified particle spectra inpp,d+Au, andAu
Abelev¹,
Aggarwal²,
Ahammed³
et al. 2009
Phys. Rev. C
906
69
905
6
View full text Add to dashboard Cite

Systematic measurements of identified particle spectra inpp,d+Au, andAu
Abelev¹,
Aggarwal²,
Ahammed³
et al. 2009
Phys. Rev. C
906
69
905
6
View full text Add to dashboard Cite

New Results in Light-Front Phenomenology

Comparative energy dependence of proton and pion degradation in diamond

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Pion Absorption in Nuclei

Cited by 141 publications

References 76 publications

Systematic measurements of identified particle spectra inpp,d+Au, andAuAbelev1, Aggarwal2, Ahammed3 et al. 2009Phys. Rev. C906699056View full textAdd to dashboardCite

Systematic measurements of identified particle spectra inpp,d+Au, andAuAbelev1, Aggarwal2, Ahammed3 et al. 2009Phys. Rev. C906699056View full textAdd to dashboardCite

New Results in Light-Front Phenomenology

Comparative energy dependence of proton and pion degradation in diamond

Contact Info

Product

Resources

About

Systematic measurements of identified particle spectra inpp,d+Au, andAu
Abelev¹,
Aggarwal²,
Ahammed³
et al. 2009
Phys. Rev. C
906
69
905
6
View full text Add to dashboard Cite

Systematic measurements of identified particle spectra inpp,d+Au, andAu
Abelev¹,
Aggarwal²,
Ahammed³
et al. 2009
Phys. Rev. C
906
69
905
6
View full text Add to dashboard Cite