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NSR database version of April 11, 2024.

Search: Author = J.Niskanen

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2020NI03      Phys.Rev. C 102, 024002 (2020)

J.A.Niskanen

Centrifugal effects in NΔ states

doi: 10.1103/PhysRevC.102.024002
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2017NI08      Phys.Rev. C 95, 054002 (2017)

J.A.Niskanen

Width of NΔ and ΔΔ states

doi: 10.1103/PhysRevC.95.054002
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2015NI13      Phys.Rev. C 92, 055205 (2015)

J.A.Niskanen

η-nuclear interaction: Optical model versus coupled-channels approach

NUCLEAR REACTIONS 3He, 12C(η, η), E=low energy; calculated scattering lengths using optical model and coupled-channel approach to study the effect of pionic inelasticity.

doi: 10.1103/PhysRevC.92.055205
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2013MA28      Nucl.Phys. A901, 65 (2013)

H.Machner, J.Haidenbauer, F.Hinterberger, A.Magiera, J.A.Niskanen, J.Ritman, R.Siudak

Study of the Λp interaction close to the Σ+ and Σ0p thresholds

NUCLEAR REACTIONS 1H(Λ, Λ), (Λ, Σ+), (Λ, Σ0), E at 400-1000 MeV/c;1H(p, Λ)pK+, (p, Σ+)nK+, (p, Σ+)pΣ0, E at ≈ 3 GeV/c;2H(K-, π-)pΛ, E at 0.76 GeV/c; calculated, analyzed missing mass, σ(θ); deduced hyperon-nucleon interaction details, resonance effects.

doi: 10.1016/j.nuclphysa.2013.01.031
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2013NI08      Nucl.Phys. A902, 40 (2013)

J.A.Niskanen, H.Machner

Binding vs. scattering length: η in light nuclei

NUCLEAR STRUCTURE 4He, 12C, 24Mg mesic nuclei; calculated scattering length vs s-state η-mesic nuclei binding energy.

doi: 10.1016/j.nuclphysa.2013.02.009
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2012PA31      Eur.Phys.J. A 48, 119 (2012)

T.M.Partanen, J.A.Niskanen, M.J.Iqbal

Parity nonconserving proton-proton elastic scattering

NUCLEAR REACTIONS 1H(p, p), E=1-350 MeV; calculated longitudinal analyzing power using DDH potential with short-range ρ and ω and longer-ranged 2π exchanges as parity nonconserving interactions.

doi: 10.1140/epja/i2012-12119-1
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2011PA19      Eur.Phys.J. A 47, 53 (2011)

T.M.Partanen, J.A.Niskanen

Parity nonconservation in deuteron photoreactions

NUCLEAR REACTIONS 2H(polarized γ, n), E=threshold-10 MeV; 1H(polarized n, γ), E=thermal-10 MeV;calculated σ with E1, M1 components, parity nonconserving components, asymmetry. Leading-order electromagnetic Hamiltonian with different interactions and Δ isobar excitations using coupled channels.

doi: 10.1140/epja/i2011-11053-0
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2009BU08      Phys.Rev. C 79, 061001 (2009)

A.Budzanowski, A.Chatterjee, P.Hawranek, F.Hinterberger, R.Jahn, V.Jha, K.Kilian, Da.Kirillov, Di.Kirillov, S.Kliczewski, D.Kolev, M.Kravcikova, M.Lesiak, J.Lieb, H.Machner, A.Magiera, R.Maier, G.Martinska, S.Nedev, J.A.Niskanen, N.Piskunov, D.Protic, J.Ritman, P.von Rossen, B.J.Roy, I.Sitnik, R.Siudak, H.J.Stein, R.Tsenov, J.Urban, G.Vankova, C.Wilkin, and the COSY-GEM Collaboration

Precision measurements of the pp → π+pn and pp → π+d reactions: Importance of long-range and tensor force effects

NUCLEAR REACTIONS p(p, X), (p, π+)d, (p, π+)pn, E=401, 601, 951 MeV; measured forward differential cross sections for pion production; deduced normalization factor for the deuteron- and pn-outgoing channels using the Faldt-Wilkin theorem.

doi: 10.1103/PhysRevC.79.061001
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2008NI08      Eur.Phys.J. A 36, 295 (2008)

J.A.Niskanen, T.M.Partanen, M.J.Iqbal

Parity nonconserving two-pion exchange in elastic proton-proton scattering

NUCLEAR REACTIONS 1H(polarized p, p), E=10-1000 MeV; calculated analyzing power using various models. Comparison with data.

doi: 10.1140/epja/i2007-10595-x
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2006MA56      Nucl.Phys. A776, 172 (2006)

H.Machner, J.A.Niskanen

Charge independence studied in NN → dπ reactions

NUCLEAR REACTIONS 1H(p, π+), (n, π0), E ≈ threshold; analyzed σ(θ), σ, anisotropies; deduced parameters, charge independence features.

doi: 10.1016/j.nuclphysa.2006.07.034
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2006NI15      Phys.Lett. B 642, 34 (2006)

J.A.Niskanen

Predictions of striking energy and angular dependence in pp → (pp)s-waveπ0 production

NUCLEAR REACTIONS 1H(p, pπ0), E=300-900 MeV; calculated σ, σ(θ). Comparison with COSY data.

doi: 10.1016/j.physletb.2006.06.083
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2006NO08      Phys.Lett. B 639, 465 (2006)

A.Nogga, A.C.Fonseca, A.Gardestig, C.Hanhart, C.J.Horowitz, G.A.Miller, J.A.Niskanen, U.van Kolck

Realistic few-body physics in the dd → απ0

NUCLEAR REACTIONS 2H(d, π0), E=293 MeV; calculated σ, related matrix elements. Effective field theory with four-body theory.

doi: 10.1016/j.physletb.2006.04.058
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2005AB01      Phys.Lett. B 610, 31 (2005)

M.Abdel-Bary, A.Budzanowski, A.Chatterjee, J.Ernst, P.Hawranek, F.Hinterberger, V.Jha, K.Kilian, S.Kliczewski, D.Kirillov, D.Kolev, M.Kravcikova, T.Kutsarova, M.Lesiak, J.Lieb, H.Machner, A.Magiera, R.Maier, G.Martinska, S.Nedev, J.Niskanen, N.Piskunov, D.Prasuhn, D.Protic, P.von Rossen, B.J.Roy, I.Sitnik, R.Siudak, M.Smiechowicz, R.Tsenov, M.Ulicny, J.Urban, G.Vankova, C.Wilkin, and the GEM Collaboration

Detailed comparison of the pp → π+ pn and pp → π+d reactions at 951 MeV

NUCLEAR REACTIONS 1H(p, pπ+), (p, π+), E=951 MeV; measured missing mass spectra, σ; deduced D-state effects.

doi: 10.1016/j.physletb.2005.01.100
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Data from this article have been entered in the EXFOR database. For more information, access X4 datasetO0819.


2004GA22      Phys.Rev. C 69, 044606 (2004)

A.Gardestig, C.J.Horowitz, A.Nogga, A.C.Fonseca, C.Hanhart, G.A.Miller, J.A.Niskanen, U.van Kolck

Survey of charge symmetry breaking operators for dd → απ0

NUCLEAR REACTIONS 2H(d, π0), E=228.5, 231.8 MeV; calculated pion production total σ, charge symmetry breaking amplitudes; deduced reaction mechanism features. Effective field theory approach.

doi: 10.1103/PhysRevC.69.044606
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2004SI30      Phys.Rev. C 70, 047001 (2004)

A.Sibirtsev, J.Haidenbauer, J.A.Niskanen, U.-G.Meissner

Bounds on the bound η-3He system

ATOMIC PHYSICS, Mesic-atoms 3He; analyzed η-3He scattering length, related data; deduced limits on bound state energy, width.

doi: 10.1103/PhysRevC.70.047001
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2004SI32      Eur.Phys.J. A 22, 495 (2004)

A.Sibirtsev, J.Haidenbauer, C.Hanhart, J.A.Niskanen

The ηHe scattering length revisited

NUCLEAR REACTIONS 2H(p, X)3He, E ≈ threshold; analyzed η-meson production data; deduced η3He scattering length.

doi: 10.1140/epja/i2003-10239-3
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2003BA17      Eur.Phys.J. A 16, 437 (2003)

V.Baru, J.Haidenbauer, C.Hanhart, J.A.Niskanen

New parameterization of the trinucleon wave function and its application to the π 3He scattering length

NUCLEAR STRUCTURE A=3; calculated wave functions. Separable parameterization.

NUCLEAR REACTIONS 3He(π, X), E not given; calculated scattering length.

doi: 10.1140/epja/i2002-10119-4
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2003BA80      Phys.Rev. C 68, 035203 (2003)

V.Baru, J.Haidenbauer, C.Hanhart, J.A.Niskanen

Charge symmetry breaking as a probe for the real part of η-nucleus scattering lengths

NUCLEAR REACTIONS 2H(p, π+), (p, π0), E at 1530-1590 MeV/c; calculated σ ratio, charge-symmetry breaking effects; deduced η-nucleus scattering lengths.

doi: 10.1103/PhysRevC.68.035203
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2003OP01      Phys.Rev.Lett. 91, 212302 (2003)

A.K.Opper, E.Korkmaz, D.A.Hutcheon, R.Abegg, C.A.Davis, R.W.Finlay, P.W.Green, L.G.Greeniaus, D.V.Jordan, J.A.Niskanen, G.V.O'Rielly, T.A.Porcelli, S.D.Reitzner, P.L.Walden, S.Yen

Charge Symmetry Breaking in np → dπ0

NUCLEAR REACTIONS 1H(n, π0), E=279.5 MeV; measured σ(θ), forward-backward asymmetry; deduced charge symmetry breaking. Comparison with model predictions.

doi: 10.1103/PhysRevLett.91.212302
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2003SC11      Phys.Rev. C 67, 044003 (2003)

S.Schneider, J.Haidenbauer, C.Hanhart, J.A.Niskanen

Positive pion absorption on 3He using modern trinucleon wave functions

NUCLEAR REACTIONS 3He(π+, p), E=120, 206, 250 MeV; calculated pion absorption σ(θ), polarization, wave function dependence. 1H(p, π+), E=515, 800 MeV; calculated analyzing power. Trinucleon wave functions, comparison with data.

doi: 10.1103/PhysRevC.67.044003
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2002BE46      Phys.Rev. C65, 064001 (2002)

M.Betigeri, J.Bojowald, A.Budzanowski, A.Chatterjee, J.Ernst, L.Freindl, D.Frekers, W.Garske, K.Grewer, A.Hamacher, J.Ilieva, L.Jarczyk, K.Kilian, S.Kliczewski, W.Klimala, D.Kolev, T.Kutsarova, J.Lieb, H.Machner, A.Magiera, R.Maier, H.Nann, J.Niskanen, D.Prasuhn, L.Pentchev, D.Protic, B.Razen, P.von Rossen, B.J.Roy, R.Siudak, A.Strzalkowski, R.Tsenov, K.Zwoll

Measurement of the pp → ppπ0 Reaction at 850 MeV/c and Partial Wave Cross Sections

NUCLEAR REACTIONS 1H(p, pπ0), E at 850 MeV/c; measured missing mass, σ(E); deduced σ. Comparison with previous results, model predictions.

doi: 10.1103/PhysRevC.65.064001
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2002NI02      Phys.Rev. C65, 037001 (2002)

J.A.Niskanen

Charge Symmetry Breaking in NN Scattering with an Interaction from Effective Field Theory

doi: 10.1103/PhysRevC.65.037001
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2000NI12      Acta Phys.Pol. B31, 2683 (2000)

J.A.Niskanen

Isospin Violation in Pion Production

NUCLEAR REACTIONS 1H(n, π0), E ≈ threshold; calculated forward-backward charge asymmetry, related features.


2000OP01      Nucl.Phys. A663-664, 505c (2000)

A.K.Opper, E.G.Auld, R.M.Churchman, C.A.Davis, R.W.Finlay, P.W.Green, L.G.Greeniaus, D.A.Hutcheon, D.V.Jordan, E.J.Korkmaz, J.A.Niskanen, G.V.O'Rielly, T.Porcelli, S.D.Reitzner, P.L.Walden, S.Yen

Charge Symmetry Breaking in the Reaction np → dπ0

NUCLEAR REACTIONS 1H(n, π0), E=279.5 MeV; measured deuteron spectra, forward-backward asymmetry.

doi: 10.1016/S0375-9474(99)00642-9
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2000VA26      Phys.Lett. 493B, 65 (2000)

U.van Kolck, J.A.Niskanen, G.A.Miller

Charge Symmetry Violation in pn → dπ0 and Chiral Effective Field Theory

NUCLEAR REACTIONS 1H(n, π0), E(cm)=279.5 MeV; calculated integrated forward-backward asymmetry in σ(θ) near threshold. Charge symmetry violation discussed in connection with future experiments.

doi: 10.1016/S0370-2693(00)01133-3
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1999FU09      Nucl.Phys. A655, 495 (1999)

C.Furget, J.Goy, S.Kox, J.S.Real, J.Arvieux, E.J.Beise, L.Bimbot, E.Brash, H.Breuer, G.Collins, F.Duncan, J.E.Ducret, M.Garcon, R.Gilman, C.Glashausser, V.P.Ladygine, M.Morlet, F.Merchez, J.Niskanen, P.Rutt, E.Tomasi-Gustafsson, E.Voutier

Measurement of Vector-Tensor Spin-Transfer Observables for the Reaction H(p(pol), d(pol))π+ between 580 and 1300 MeV

NUCLEAR REACTIONS 1H(polarized p, π+), E=580-1300 MeV; measured deuterons σ(θ), analyzing power, tensor polarization, spin-transfer coefficients. Partial wave analysis, coupled channels model calculation.

doi: 10.1016/S0375-9474(99)00302-4
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1999HA06      Phys.Rev.Lett. 82, 2258 (1999)

H.Hahn, F.A.Duncan, J.Aclander, D.Ashery, E.G.Auld, D.R.Gill, D.A.Hutcheon, G.Jones, E.Korkmaz, S.Maytal-Beck, M.A.Moinester, J.A.Niskanen, D.Ottewell, A.Rahav, S.Ram, M.Sevior, P.L.Walden, R.Weiss

Analyzing Powers and Partial Wave Decomposition of pn → pp(1S0- at Low Energies

NUCLEAR REACTIONS 2H(polarized p, 2pπ-), E=353, 403, 440 MeV; measured pion, proton spectra, spectator momentum distributions. 1n(polarized p, pπ-)E=353, 403, 440 MeV; deduced analyzing powers for quasifree reaction. Partial wave analysis.

doi: 10.1103/PhysRevLett.82.2258
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1999NI02      Phys.Lett. 456B, 107 (1999)

J.A.Niskanen

Test of Final State Approximations using Threshold pp → ppπ0

NUCLEAR REACTIONS 1H(p, pπ0), E ≈ threshold; calculated transition matrix momentum dependence; deduced final state approximation features. Watson-Migdal method.

doi: 10.1016/S0370-2693(99)00480-3
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1999NI06      Few-Body Systems 26, 241 (1999)

J.A.Niskanen

Isospin Breaking in the Reaction np → dπ0 at Threshold

NUCLEAR REACTIONS 1H(n, π0), E=278-350 MeV; calculated forward-backward asymmetry, meson mixing contributions.

doi: 10.1007/s006010050117
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1998DU07      Phys.Rev.Lett. 80, 4390 (1998)

F.Duncan, H.Hahn, C.Aclander, D.Ashery, E.G.Auld, D.R.Gill, D.A.Hutcheon, G.Jones, E.Korkmaz, S.Maytal-Beck, M.A.Moinester, J.A.Niskanen, D.Ottewell, A.Rahav, S.Ram, M.Sevior, P.L.Walden, R.Weiss

Differential Cross Section of the pn → pp(1S0- Reaction Extracted from pd → pppπ-

NUCLEAR REACTIONS 2H(polarized p, 2pπ-), E=353, 403, 440 MeV; measured spectator momentum distributions; deduced σ(θ(π), M(pp)) for pn reaction. Comparison with pion absorption data.

doi: 10.1103/PhysRevLett.80.4390
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1997NI03      Phys.Lett. 394B, 253 (1997)

J.A.Niskanen, M.Vestama

Charge Dependence of NN → dπ

NUCLEAR REACTIONS 1H(polarized n, π0), (polarized p, π+), E not given; calculated analyzing power at θ=90° vs parameter η; deduced isospin symmetry violating effects related features.

doi: 10.1016/S0370-2693(97)00005-1
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1996CO02      Phys.Rev. C53, 1154 (1996)

S.A.Coon, J.A.Niskanen

Two-Pion Exchange Contributions to Nuclear Charge Asymmetry

NUCLEAR STRUCTURE 3H, 3He; calculated binding energy difference. Charge-symmetry-breaking two-pion exchange interaction.

doi: 10.1103/PhysRevC.53.1154
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1996GR17      Phys.Rev. C54, 1970 (1996)

A.M.Green, J.A.Niskanen, S.Wycech

η-Deuteron Scattering

NUCLEAR REACTIONS 2H(X, X), E=low; calculated ηd-scattering length; deduced need to go beyond fixed nucleon approximation.

doi: 10.1103/PhysRevC.54.1970
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1996NI01      Phys.Rev. C53, 526 (1996)

J.A.Niskanen

Comment on ' Role of Heavy Meson Exchange in Near Threshold NN → dπ '

NUCLEAR REACTIONS 1H(p, π+), E=low; calculated σ/(q(π)/m(π)). 1H(polarized p, π+), E=290.7, 515 MeV; calculated analyzing power vs θ; deduced heavy meson exchange related features.

doi: 10.1103/PhysRevC.53.526
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1996NI16      Acta Phys.Pol. B27, 2845 (1996)

J.A.Niskanen

Pion Production as a Probe of Two-Nucleon Axial Charge and Current


1996WI03      Nucl.Phys. A597, 613 (1996)

P.Wilhelm, J.A.Niskanen, H.Arenhovel

Signatures from Polarization Observables for Photon Absorption on a 1S0 Proton Pair

doi: 10.1016/0375-9474(95)00458-0
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1995NI07      Nucl.Phys. A586, 693 (1995)

J.A.Niskanen, P.Wilhelm, H.Arenhovel

Quasifree Photoabsorption on Neutron-Proton Pairs in 3He

NUCLEAR REACTIONS 3He(γ, np), (polarized γ, np), E=200-400 MeV; calculated photoabsorption σ(E), σ(θp), proton polarization, analyzing power, asymmetry vs θ. Quasifree absorption, nucleonic, meson exchange currents, Δ(1232)-isobar excitation.

doi: 10.1016/0375-9474(95)00037-2
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1995NI13      Phys.Lett. 359B, 295 (1995)

J.A.Niskanen, P.Wilhelm

Pion vs. Photon Absorption on the Deuteron

NUCLEAR REACTIONS 2H(π+, p), E not given; calculated absorption σ vs pion momentum. 2H(γ, n), E=140-440 MeV; calculated photodisintegration σ(E).

doi: 10.1016/0370-2693(95)01105-Y
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1995WI14      Phys.Rev.Lett. 74, 1034 (1995)

P.Wilhelm, H.Arenhovel, J.A.Niskanen

Comment on ' Total Cross Section for Photon Absorption by Two Protons in 3He '

NUCLEAR REACTIONS 3He(γ, X), E ≈ 200-500 MeV; analyzed, reanalyzed σ(E) data analyses; deduced nonnegligible E1 multipole contribution.

doi: 10.1103/PhysRevLett.74.1034
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1995WI16      Phys.Rev. C51, 2841 (1995)

P.Wilhelm, J.A.Niskanen, H.Arenhovel

Photon Absorption on a Proton-Proton Pair in 3He

NUCLEAR REACTIONS 3He(γ, 2p), E=100-500 MeV; analyzed σ(E); deduced various multipole contributions, photon absorption mechanism, Δ role. Different models.

doi: 10.1103/PhysRevC.51.2841
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1995WY01      Phys.Rev. C52, 544 (1995)

S.Wycech, A.M.Green, J.A.Niskanen

Are There η-Helium Bound States ( Question )

NUCLEAR REACTIONS 2H(p, X), (d, X), E not given; calculated eta production (amplitude)2, amplitude vs eta momentum; deduced (eta-4He) quasibound state evidence. Multiple scattering theory.

doi: 10.1103/PhysRevC.52.544
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1994IQ01      Phys.Rev. C49, 355 (1994)

M.J.Iqbal, J.A.Niskanen

Isobar Excitation in Parity Nonconserving Proton-Proton Scattering

NUCLEAR REACTIONS 1H(polarized p, p), E=10-1000 MeV; calculated parity violating average longitudinal analyzing power. Meson exchange model, isobar excitation.

doi: 10.1103/PhysRevC.49.355
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1994IQ02      Phys.Lett. 322B, 7 (1994)

M.J.Iqbal, J.A.Niskanen

The Effect of Off-Shell Variations of (ρ(Omega)) Meson Mixing on Charged Symmetry Breaking Neutron-Proton Scattering

NUCLEAR REACTIONS 1n(polarized p, p), E=183-800 MeV; calculated charge symmetry breaking observable vs θ; deduced ρ(omega)-mixing matrix off-shell variations implications.

doi: 10.1016/0370-2693(94)90482-0
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1994NI02      Phys.Rev. C49, 1285 (1994)

J.A.Niskanen

Impact of pp → ppπ0 Data to Negative-Pion Absorption on Proton Pairs

NUCLEAR REACTIONS 1H(p, pπ0), E=290 MeV; calculated σ vs pion momentum. 3He(π-, X), E=62.5 MeV; calculated σ(θ), pion absorption on diproton. 1n(polarized p, pπ-), E=62.5; calculated polarization vs θ. 3He(π-, X), E=50-250 MeV; calculated absorption σ vs E.

doi: 10.1103/PhysRevC.49.1285
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1994WI12      Phys.Lett. 335B, 109 (1994)

P.Wilhelm, J.A.Niskanen, H.Arenhovel

Photon Absorption on a Neutron-Proton Pair in 3He

NUCLEAR REACTIONS 3He(γ, np), E=245 MeV; calculated σ(θ); deduced spectator role importance. Quasifree two-body model.

doi: 10.1016/0370-2693(94)91399-4
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1993AC01      Phys.Lett. 300B, 19 (1993)

J.Aclander, S.May Tal-Beck, A.Altman, D.Ashery, H.Hahn, M.A.Moinester, A.Rahav, A.Feltham, G.Jones, M.Pavan, M.Sevior, D.Hutcheon, D.Ottewell, G.R.Smith, J.A.Niskanen

Proton Polarization from π+ Absorption in 4He

NUCLEAR REACTIONS 3,4He(π+, pX), E=120, 250 MeV; 2H(π+, p), E=120, 250 MeV; measured proton polarization, undetected nucleon yield.

doi: 10.1016/0370-2693(93)90741-Y
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1993ME03      Phys.Rev. C47, R2474 (1993)

H.O.Meyer, J.A.Niskanen

Quasifree Pion Production in the Three-Nucleon System

NUCLEAR REACTIONS 1n(p, π0), 2H(p, pπ0), E not given; calculated σ; deduced quasifree process role in pd → pdπ0.

doi: 10.1103/PhysRevC.47.2474
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1992MA17      Phys.Rev.Lett. 68, 3012 (1992)

S.May Tal-Beck, J.Aclander, A.Altman, D.Ashery, H.Hahn, M.A.Moinester, A.Rahav, A.Feltham, G.Jones, M.Pavan, M.Sevior, D.Hutcheon, D.Ottewell, G.R.Smith, J.A.Niskanen

Proton Polarization from π+ Absorption in 3He

NUCLEAR REACTIONS 3He(π+, p), E=120, 250 MeV; measured proton polarization vs θ following pion absorption; deduced nuclear density dependence, short range correlations role. Quasideuteron absorption kinematics.

doi: 10.1103/PhysRevLett.68.3012
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1992NI05      Phys.Rev. C45, 3021 (1992)

J.A.Niskanen, S.E.Vigdor

Effect of Inelasticity in Charge Sysmmetry Breaking Neutron-Proton Scattering

NUCLEAR REACTIONS 1H(polarized n, n), E=800 MeV; calcualted symmetry breaking obsevable ΔA(θ), charge symmetric A(θ); deduced inelasticity role.

doi: 10.1103/PhysRevC.45.3021
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1992NI08      Phys.Lett. 289B, 227 (1992)

J.A.Niskanen

Energy Dependence of the pp → (pp) (S-Wave) π0 Total Cross Section

NUCLEAR REACTIONS 1H(p, pπ0), E ≤ 700 MeV; calculated σ vs E; deduced rescattering effects role. Direct pion production plus pion rescattering through Δ-isobar.

doi: 10.1016/0370-2693(92)91210-Z
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1991GR17      Phys.Lett. 265B, 223 (1991)

A.M.Green, B.Moussallam, J.A.Niskanen, M.E.Sainio, S.Wycech

Violation of G-Parity in Antinucleon-Nucleon Annihilation

NUCLEAR REACTIONS 1H(n-bar, π+π0), E at 0.39 GeV/c; calculated σ asymmetry. G-parity violation.

doi: 10.1016/0370-2693(91)90045-R
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1991NI01      Phys.Rev. C43, 36 (1991)

J.A.Niskanen

π- Absorption on the Diproton in 3He

NUCLEAR REACTIONS 3He(π-, X), E ≈ 100-200 MeV; calculated absorption σ(E), σ(θ), outgoing proton polarization. Two-nucleon final state interactions, third nucleon spectator, phenomenological Hamiltonian.

doi: 10.1103/PhysRevC.43.36
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1991NI04      Phys.Rev. C44, 2222 (1991)

J.A.Niskanen

Effect of the 1S0 Neutron Proton Pair on Positive Pion Absorption in 3He

NUCLEAR REACTIONS 3He(π+, X), E=62-250 MeV; calculated pion absorption reduced matrix amplitude, outgoing proton polarization, analyzing power vs θ; deduced isotriplet neutron-proton pair contribution estimate.

doi: 10.1103/PhysRevC.44.2222
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1990IQ01      Phys.Rev. C42, 1872 (1990)

M.J.Iqbal, J.A.Niskanen

Parity Violating Nuclear Force by Meson Mixing

NUCLEAR REACTIONS 1H(polarized p, p), E=10-1000 MeV; calculated average longitudinal analyzing power; deduced form factors, correlations role. Meson mixing, parity violating interaction.

doi: 10.1103/PhysRevC.42.1872
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1989NI01      Phys.Lett. 218B, 272 (1989)

J.A.Niskanen, M.J.Iqbal

ρ(Omega) Meson Mixing in the Reaction np → dπ0

NUCLEAR REACTIONS 1n(p, π0), E=580, 800 MeV; calculated pion production σ asymmetry; deduced ρ(omega) mixing role.

doi: 10.1016/0370-2693(89)91579-7
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1989NI05      Phys.Rev. C40, 2420 (1989)

J.A.Niskanen, L.Swift, A.W.Thomas

Pion Absorption on Polarized 3He

NUCLEAR REACTIONS 3He(π+, X), E=62-246 MeV; calculated analyzing power vs E. Polarized 3He, deuteron-like pair absorbs pion.

doi: 10.1103/PhysRevC.40.2420
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1988GE03      Few-Body Systems 3, 171 (1988)

A.Gersten, L.G.Greeniaus, J.A.Niskanen, S.Ishikawa, T.Sasakawa, A.W.Thomas

Test of Charge Symmetry in Few-Body Systems

NUCLEAR REACTIONS 1H(n, n), 2H(d, d), E not given; compiled, theoretical, experimental work; deduced charge symmetry breaking status.

doi: 10.1007/BF01077594
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1988IQ01      Phys.Rev. C38, 2259 (1988)

M.J.Iqbal, J.A.Niskanen

Charge Symmetry Breaking in Neutron-Proton Scattering Including Arbitrary Mesons

NUCLEAR REACTIONS 1n(polarized p, p), 1H(polarized n, n), E=100 MeV; analyzed polarization asymmetry data; deduced charge symmetry breaking sensitivity to meson-nucleon form factors.

doi: 10.1103/PhysRevC.38.2259
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1988NI01      Phys.Rev. C37, 1755 (1988)

J.A.Niskanen, A.W.Thomas

Possibility of Isospin Breaking in the Deuteron

NUCLEAR STRUCTURE 2H; calculated isospin mixing in wave function. Pion, nucleon, isobar mass differences.

doi: 10.1103/PhysRevC.37.1755
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1988NI06      Phys.Rev. C38, 838 (1988)

J.A.Niskanen, M.Sebestyen, A.W.Thomas

Charge Symmetry Breaking in the Reaction np → dπ0

NUCLEAR REACTIONS 1H(n, π0), E=477, 580 MeV; calculated σ(θ); deduced charge symmetry breaking effects. Coupled-channels model.

doi: 10.1103/PhysRevC.38.838
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1988NI07      Aust.J.Phys. 41, 31 (1988)

J.A.Niskanen, A.W.Thomas

Charge Symmetry Breaking in Neutron-Proton Scattering above Pion Production Threshold

NUCLEAR REACTIONS 1n(p, p), E=477-800 MeV; calculated (A(n)-A(p)); deduced nucleon-isobar channel role.

doi: 10.1071/PH880031
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1987NI09      Phys.Lett. 196B, 299 (1987)

J.A.Niskanen, A.W.Thomas

Quasi-Two-Body Pion Absorption on Helium-3

NUCLEAR STRUCTURE 3He; calculated n-p correlation function.

NUCLEAR REACTIONS 2H(π+, p), E=62-246 MeV; calculated proton polarization observables, σ(θ).

doi: 10.1016/0370-2693(87)90735-0
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1986GR25      Phys.Scr. 34, 550 (1986)

A.M.Green, J.A.Niskanen

The Effect of Short Range Repulsions on N(N-Bar) Annihilation

NUCLEAR REACTIONS 1H(p-bar, π), 1n(n-bar, π0), E=50, 100, 200 MeV; calculated total, annihilation σ. Skyrmion-antiskyrmion model.

doi: 10.1088/0031-8949/34/6A/010
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1985WY01      Phys.Lett. 152B, 308 (1985)

S.Wycech, A.M.Green, J.A.Niskanen

On the Energy Levels in Antiprotonic Deuterium

ATOMIC PHYSICS 2H(p-bar, p-bar), E at rest; calculated antiprotonic level shifts, Γ. Separable potentials.

doi: 10.1016/0370-2693(85)90501-5
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1984DU04      Nucl.Phys. A412, 195 (1984)

O.Dumbrajs, A.M.Green, J.A.Niskanen

Low-Energy Scattering Parameters and Atomic Level Shifts in the (p-bar)16O, (p-bar)32S and (p-bar)40Ca Systems

NUCLEAR REACTIONS 16O, 32S, 40Ca(p-bar, p-bar), E=low; calculated scattering parameters; deduced atomic level shift, scattering parameter relationship. Optical potential.

doi: 10.1016/0375-9474(84)90678-X
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1984MO25      Phys.Lett. 146B, 379 (1984)

A.Moalem, J.A.Niskanen, A.M.Green

Direct Formation of NN(bar) Bound States in a Single Nucleon Pickup

NUCLEAR REACTIONS 4He(p-bar, X), E=low; calculated σ(θ) for nucleon-antinucleon (X) bound states; deduced nucleon-antinucleon state parameters.

doi: 10.1016/0370-2693(84)90143-6
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1984NI07      Phys.Lett. 141B, 301 (1984)

J.A.Niskanen

Some Improvements in the Coupled Channels Calculations of the Reaction p + p → d + π+

NUCLEAR REACTIONS 1H(p, π+), E=300-800 MeV; calculated total pion production σ(E). 1H(polarized p, π+), E=580 MeV; calculated σ(θ), asymmetry vs θ. Coupled-channels, isobar contribution.

doi: 10.1016/0370-2693(84)90249-1
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1983NI07      Nucl.Phys. A404, 495 (1983)

J.A.Niskanen, A.M.Green

Antiproton Nuclear Scattering in a Microscopic Potential Model

NUCLEAR REACTIONS 12C, 16O, 32S, 40Ca(p-bar, p-bar), E=35, 75, 130 MeV; 40Ca(p-bar, p-bar), E=200 MeV; calculated σ(θ), absorption σ. Energy dependent optical model.

doi: 10.1016/0375-9474(83)90273-7
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1979NI03      Phys.Lett. 82B, 187 (1979)

J.A.Niskanen

Polarization of the Deuteron in the Reaction p + p → d + π+

NUCLEAR REACTIONS 1H(p, π+); calculated d-polarization; deduced small interaction-dependent vector, large model-independent tensor polarizations. Isobar model, different interactions.

doi: 10.1016/0370-2693(79)90732-9
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1978NI01      Nucl.Phys. A298, 417 (1978)

J.A.Niskanen

The Differential Cross Section and Polarization in p+p → d+π+

NUCLEAR REACTIONS 1H(p, π+d), E=threshold-750 MeV; calculated σ, polarization.

doi: 10.1016/0375-9474(78)90142-2
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1978NI03      Phys.Lett. 79B, 190 (1978)

J.A.Niskanen

The Reaction p + p → d + π+ with a Polarized Beam and Target

NUCLEAR REACTIONS 1H(polarized p, π+), E=300-700 MeV; calculated σ(θ); deduced D-state probability. polarized target.

doi: 10.1016/0370-2693(78)90219-8
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1977NI04      Phys.Lett. 71B, 40 (1977)

J.A.Niskanen

The Differential Cross Section and Polarization in P + P → D + π+

NUCLEAR REACTIONS 1H(p, π+d), E=threshold-750 MeV; calculated σ(E), polarization.

doi: 10.1016/0370-2693(77)90734-1
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1975GR05      Nucl.Phys. A240, 263 (1975)

A.M.Green, J.Niskanen

The Effect of Resonances in 8Be on α-α Bremsstrahlung

NUCLEAR REACTIONS 4He(α, α); calculated effect of enhanced quadrupole matrix element on bremsstrahlung σ.

doi: 10.1016/0375-9474(75)90330-9
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Note: The following list of authors and aliases matches the search parameter J.Niskanen: , J.A.NISKANEN