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5. Transverse mass distributions of neutral pions from 208Pb-induced reactions at 158 A GeV

Author

Aggarwal, M.M., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., El Chenawi, K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Karadjev, K., Karpio, K., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.J., Morrison, Douglas R.O., Mukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Peitzmann, T., Peressounko, D., Petracek, V., Plasil, F., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Rao, N.K., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., Van den Pijll, E.C., Van Eijndhoven, N., Van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., Young, G.R., and KVI - Center for Advanced Radiation Technology

Subjects
Physics and Astronomy (miscellaneous), ENERGIES, FOS: Physical sciences, PP, 01 natural sciences, Spectral line, CROSS-SECTIONS, Nuclear physics, Pion, 0103 physical sciences, CERN, SPECTRA, Rapidity, NUCLEAR COLLISIONS, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Engineering (miscellaneous), Nuclear Physics, Physics, Range (particle radiation), 010308 nuclear & particles physics, 158A GEV, 200 AGEV, MOMENTUM, MODEL, Cover (topology), Transverse mass, Impact parameter
Abstract

Results on transverse mass spectra of neutral pions measured at central rapidity are presented for impact parameter selected 158$\cdot A$ GeV Pb + Pb, and Pb + Nb collisions. The distributions cover the range $0.5 \mathrm{GeV}/c^{2} \le m_{T} - m_{0} \le 4 \mathrm{GeV}/c^{2}$. The change of the spectral shape with centrality is studied in detail. In going from peripheral to medium central collisions there is a nuclear enhancement increasing with transverse mass similar to the well known Cronin effect, while for very central collisions this enhancement appears to be weaker than expected., Comment: 11 pages, 15 figures, revised version accepted for publication in EUR.PHYS.J. C

Published
2002
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6. Central Pb+Pb collisions at 158 A GeV/c studied by π−π− interferometry

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.M., Borocz, Z., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Klein-Boesing, Christian, Knoche, S., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mgebrichvili, G., Miake, Y., Mir, M.F., Mishra, G.C., Miyamoto, Y., Mohanty, B., Morrison, Douglas R.O., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Pavliouk, S., Peitzmann, T., Petracek, V., Pinganaud, W., Plasil, F., von Poblotzki, U., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Research unit Nuclear & Hadron Physics

Subjects
Particle physics, Physics and Astronomy (miscellaneous), Gaussian, FOS: Physical sciences, HEAVY-ION COLLISIONS, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), symbols.namesake, TRACKING, Pion, SYSTEMS, Invariant (mathematics), Engineering (miscellaneous), MULTISTEP AVALANCHE CHAMBERS, PION INTERFEROMETRY, Physics, Resolution (electron density), Function (mathematics), 2-PION CORRELATIONS, PERFORMANCE, READOUT, Exponential function, Interferometry, Cross term, symbols, PB+PB COLLISIONS, Particle Physics - Experiment
Abstract

Two-particle correlations have been measured for identified negative pions from central 158 AGeV Pb+Pb collisions and fitted radii of about 7 fm in all dimensions have been obtained. A multi-dimensional study of the radii as a function of kT is presented, including a full correction for the resolution effects of the apparatus. The cross term Rout-long of the standard fit in the Longitudinally CoMoving System (LCMS) and the vl parameter of the generalised Yano-Koonin fit are compatible with 0, suggesting that the source undergoes a boost invariant expansion. The shapes of the correlation functions in Qinv and Qspace have been analyzed in detail. They are not Gaussian but better represented by exponentials. As a consequence, fitting Gaussians to these correlation functions may produce different radii depending on the acceptance of the experimental setup used for the measurement., 13 pages including 10 figures

Published
2000

7. Photon and Eta Production in p+Pb and p+C Collisions at $\sqrt{s_{NN}} = 17.4$ GeV

Author

Aggarwal, M.M., Ahammed, Z., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Baumann, C., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Majumdar, M.R.Dutta, El Chenawi, K., Dubey, A.K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Karadjev, K., Karpio, K., Kolb, B.W., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.J., Morrison, D., Mukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Pavliouk, S., Peitzmann, T., Peressounko, D., Petracek, V., Phatak, S.C., Pinganaud, W., Plasil, F., Purschke, M.L., Rak, J., Rammler, M., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., Pijll, E.C.v.d., Eijndhoven, N.v., Nieuwenhuizen, G.J.v., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Young, G.R., Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and WA98

Subjects
FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Physics - Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Measurements of direct photon production in p+Pb and p+C collisions at $\sqrt{s_{NN}}$=17.4 GeV are presented. Upper limits on the direct photon yield as a function of p_T are derived and compared to the results for Pb+Pb collisions at $\sqrt{s_{NN}}$=17.3 GeV. The production of the @h meson, which is an important input to the direct photon signal extraction, has been determined in the @h->2@c channel for p+C collisions at $\sqrt{s_{NN}}$=17.4 GeV. Measurements of direct photon production in p + Pb and p + C collisions at sNN=17.4 GeV are presented. Upper limits on the direct photon yield as a function of pT are derived and compared to the results for Pb + Pb collisions at sNN=17.3 GeV . The production of the η meson, which is an important input to the direct photon signal extraction, has been determined in the η→2γ channel for p + C collisions at sNN=17.4 GeV . Measurements of direct photon production in p+Pb and p+C collisions at $\sqrt{s_\mathrm{NN}} = 17.4\mathrm{GeV}$ are presented. Upper limits on the direct photon yield as a function of $p_\mathrm{T}$ are derived and compared to the results for Pb+Pb collisions at $\sqrt{s_\mathrm{NN}} = 17.3$ GeV. The production of the $\eta$ meson, which is an important input to the direct photon signal extraction, has been determined in the $\eta \rightarrow 2\gamma$ channel for p+C collisions at $\sqrt{s_\mathrm{NN}} = 17.4\mathrm{GeV}$.

Published
2011
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8. Event-by-event charged-neutral fluctuations in Pb+Pb collisions at 158 A~GeV

Author

Aggarwal, M.M., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., El Chenawi, K., Dubey, A.K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, R., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Karadjev, K., Karpio, K., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Liu, H., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.J., Morrison, D., Moukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Pavliouk, S., Peitzmann, T., Peressounko, D., Petracek, V., Pinanaud, W., Plasil, F., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., and Young, G.R.

Subjects
FOS: Physical sciences, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Charged particles and photons have been measured in central Pb+Pb collisions at 158 A GeV in a common ($\eta$ - $\phi$)-phase space region in the WA98 experiment at the CERN SPS. The measured distributions have been analyzed %using the sliding window method in order to quantify the frequency with which phase space regions of varying sizes have either small or large neutral pion fraction. The measured results are compared with VENUS model simulated events and with mixed events. Events with both large and small charged-neutral fluctuations are observed to occur more frequently than expected statistically, as deduced from mixed events, or as predicted by model simulations, with the difference becoming more prominent with decreasing size of the $\Delta\eta$ - $\Delta\phi$ region., Comment: six pages, six figures

Published
2011

9. Suppression of High-pT Neutral Pions in Central Pb+Pb Collisions at sqrt{s_NN} = 17.3 GeV

Author

Aggarwal, M.M., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Baumann, C., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., El Chenawi, K., Dubey, A.K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Karadjev, K., Karpio, K., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.J., Morrison, D., Mukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Pavliouk, S., Peitzmann, T., Peressounko, D., Petracek, V., Phatak, S.C., Pinganaud, W., Plasil, F., Purschke, M.L., Rak, J., Rammler, M., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., and Young, G.R.

Subjects
Nuclear Theory, High Energy Physics::Experiment, Nuclear Physics - Experiment, Nuclear Experiment
Abstract

Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at sqrt{s_NN} = 17.4 GeV at mid-rapidity (2.3 2 GeV/c is consistent with the p+C or p+Pb yields scaled with the number of inelastic nucleon-nucleon collisions, while for central Pb+Pb collisions with N_{part} > 300 the pion yield is suppressed.

Published
2007

10. Suppression of High-p_T Neutral Pion Production in Central Pb+Pb Collisions at sqrt{s_NN} = 17.3 GeV Relative to p+C and p+Pb Collisions

Author

Aggarwal, M.M., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Baumann, Cédric, Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., El Chenawi, K., Dubey, A.K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gustafsson, H.A., H.Gutbrod, H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Karadjev, K., Karpio, K., W. Kolb, B., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez Garcia, Gines, Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.-J., Morrison, D., Mukhanova, T., S. Mukhopadhyay, D., Naef, H., K. Nandi, B., K. Nayak, S., K. Nayak, T., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Pavliouk, S., Peitzmann, T., Peressounko, D., Petracek, V., Phatak, S.C., Pinganaud, W., Plasil, F., Purschke, M.L., Rak, J., Rammler, M., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., Pijll, E.C.V.D., Eijndhoven, N.V., Nieuwenhuizen, G.J.V., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wys Louch, B., Young, G.R., Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and WA98

Subjects
13.87.Ce,13.87.Fh,25.75.-q,25.75.Dw, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at sqrt{s_NN} = 17.4 GeV at mid-rapidity 2.3 < eta_lab < 3.0 over the range 0.7< p_T < 3.5 GeV/c. The spectra are compared to pi0 spectra measured in Pb+Pb collisions at sqrt{s_NN} = 17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N_part < 300) the yield of pi0's with p_T > 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaled with the number of nucleon-nucleon collisions (N_coll), while for central Pb+Pb collisions with N_part > 350 the pi0 yield is suppressed., 5 pages, 4 figures

Published
2007
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11. Azimuthal Anisotropy of Photon and Charged Particle Emission in Pb+Pb Collisions at 158 A GeV/c

Author

Aggarwal, M.M., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Areev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Bernier, T., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., Dubey, A.K., El Chenawi, K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Karadjev, K., Karpio, K., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez Garcia, Gines, Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.-J., Morrison, D., Moukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Peitzmann, T., Peressounko, D., Petracek, V., Phatak, S.C., Pinganaud, W., Plasil, F., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., Van Der Pijll, E.C., Van Eijndhoven, N., Van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Young, G.R., Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and WA98

Subjects
FOS: Physical sciences, Nuclear Physics - Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The azimuthal distributions of photons and charged particles with respect to the event plane are investigated as a function of centrality in Pb + Pb collisions at 158 A GeV/c in the WA98 experiment at the CERN SPS. The anisotropy of the azimuthal distributions is characterized using a Fourier analysis. For both the photon and charged particle distributions the first two Fourier coefficients are observed to decrease with increasing centrality. The observed anisotropies of the photon distributions compare well with the expectations from the charged particle measurements for all centralities., 8 pages and 6 figures. The manuscript has undergone a major revision. The unwanted correlations were enhanced in the random subdivision method used in the earlier version. The present version uses the more established method of division into subevents separated in rapidity to minimise short range correlations. The observed results for charged particles are in agreement with results from the other experiments. The observed anisotropy in photons is explained using flow results of pions and the correlations arising due to the decay of the neutral pions

Published
2004
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12. One-, two-, and three-particle distributions from 158A GeV/c central Pb+Pb collisions

Author

Aggarwal, M M, Angelis, A L S, Antonenko, V, Arefiev, V, Astakhov, V, Avdeitchikov, V, Awes, TC, Baba, P V K S, Badyal, K, Bathe, S, Batiounia, B, Bernier, T, Bhalla, KB, Bhatia, VS, Blume, C, Bucher, D, Busching, H, Carlen, L, Chattopadhyay, S, Decowski, MP, Delagrange, H, Donni, P, Majumdar, MRD, El Chenawi, K, Enosawa, K, Fokin, S, Frolov, V, Ganti, MS, Garpman, S, Gavrishchuk, O, Geurts, FJM, Ghosh, T K, Glasow, R, Guskov, B, Gustafsson, H.A., Gutbrod, HH, Hrivnacova, I., Ippolitov, M, Kalechofsky, H, Kamermans, R, Karadjev, K, Karpio, K, Kolb, BW, Kosarev, I., Koutcheryaev, I., Kugler, A, Kulinich, P, Kurata, M, Lebedev, A, Lohner, H, Mahapatra, DP, Manko, V., Martin, M, Martinez, G, Maximov, A, Miake, Y, Mishra, GC, Mohanty, B, Mora, MJ, Morrison, D, Mukhanova, T, Mukhopadhyay, DS, Naef, H, Nandi, BK, Nayak, SK, Nayak, TK, Nianine, A, Nikitine, V, Nikolaev, S, Nilsson, P, Nishimura, S, Nomokonov, P, Nystrand, J, Oskarsson, A, Otterlund, I., Peitzmann, T, Peressounko, D, Petracek, V., Plasil, F, Purschke, ML, Rak, J, Raniwala, R, Raniwala, S, Rao, NK, Reygers, K, Roland, G, Rosselet, L, Roufanov, I, Rubio, JM, Sambyal, SS, Santo, R, Sato, S, Schlagheck, H, Schutz, Y, Shabratova, G, Shah, TH, Sibiriak, I., Siemiarczuk, T, Silvermyr, D, Sinha, BC, Slavine, N, Soderstrom, K, Sood, G, Sorensen, SP, Stankus, P, Stefanek, G, Steinberg, P, Stenlund, E, Sumbera, M, Svensson, T, Tsvetkov, A., Tykarski, L, v d Pijll, EC, v Eijndhoven, N, v Nieuwenhuizen, GJ, Vinogradov, A, Viyogi, YP, Vodopianov, A, Voros, S, Wyslouch, B, Young, GR, and Research unit Nuclear & Hadron Physics

Subjects
TWISS CORRELATION RADII, Nuclear Theory, 3-PION INTERFEROMETRY, MULTISTEP AVALANCHE CHAMBER, PHASE-SPACE DENSITY, NUCLEAR COLLISIONS, HEAVY-ION COLLISIONS, 2-PION CORRELATIONS, PERFORMANCE, Nuclear Experiment, PLUS PB COLLISIONS, PION INTERFEROMETRY
Abstract

Several hadronic observables have been studied in central 158A GeV Pb+Pb collisions using data measured by the WA98 experiment at CERN: single pi(-) and K- production, as well as two- and three-pion interferometry. The Wiedemann-Heinz hydrodynamical model has been fitted to the pion spectrum, giving an estimate of the temperature and transverse flow velocity. Bose-Einstein correlations between two identified pi(-) have been analyzed as a function of k(T), using two different parametrizations. The results indicate that the source does not have a strictly boost invariant expansion or spend time in a long-lived intermediate phase. A comparison between data and a hydrodynamical based simulation shows very good agreement for the radii parameters as a function of k(T). The pion phase-space density at freeze-out has been measured, and agrees well with the Tomasik-Heinz model. A large pion chemical potential close to the condensation limit of m(pi) seems to be excluded. The three-pion Bose-Einstein interferometry shows a substantial contribution of the genuine three-pion correlation, but not quite as large as expected for a fully chaotic and symmetric source.

Published
2003

13. Centrality dependence of charged-neutral particle fluctuations in 158A GeV Pb+Pb collisions

Author

Aggarwal, M.M., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., El Chenawi, K., Dubey, A.K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Karadjev, K., Karpio, K., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.J., Morrison, D., Mukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Peitzmann, T., Peressounko, D., Petracek, V., Pinganaud, W., Plasil, F., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., and Young, G.R.

Subjects
Nuclear Physics
Abstract

Results on the study of localized fluctuations in the multiplicity of charged particles and photons produce 158A GeV/c Pb+Pb collisions are presented for four different centrality classes. The charged versus neutral particle multiplicity correlations in common phase space regions of varying azimuthal size are analyzed by two different methods. Various types of mixed events are constructed to probe fluctuations arising from different sources. The measured results are compared to those from simulations and from mixed events. The comparison indicates the presence of non-statistical fluctuations in both the charged particle and photon multiplicities in limited azimuthal regions which decrease with decrease in centrality. However, no correlated charged-neutral fluctuations, a possible signature of formation of disoriented chiral condensates, are observed. An upper limit on the production of disoriented chiral condensates has been set. Results on the study of localized fluctuations in the multiplicity of charged particles and photons produce 158A GeV/c Pb+Pb collisions are presented for four different centrality classes. The charged versus neutral particle multiplicity correlations in common phase space regions of varying azimuthal size are analyzed by two different methods. Various types of mixed events are constructed to probe fluctuations arising from different sources. The measured results are compared to those from simulations and from mixed events. The comparison indicates the presence of non-statistical fluctuations in both the charged particle and photon multiplicities in limited azimuthal regions which decrease with decrease in centrality. However, no correlated charged-neutral fluctuations, a possible signature of formation of disoriented chiral condensates, are observed. An upper limit on the production of disoriented chiral condensates has been set. Results on the study of localized fluctuations in the multiplicity of charged particles and photons produce 158A GeV/c Pb+Pb collisions are presented for four different centrality classes. The charged versus neutral particle multiplicity correlations in common phase space regions of varying azimuthal size are analyzed by two different methods. Various types of mixed events are constructed to probe fluctuations arising from different sources. The measured results are compared to those from simulations and from mixed events. The comparison indicates the presence of non-statistical fluctuations in both the charged particle and photon multiplicities in limited azimuthal regions which decrease with decrease in centrality. However, no correlated charged-neutral fluctuations, a possible signature of formation of disoriented chiral condensates, are observed. An upper limit on the production of disoriented chiral condensates has been set.

Published
2002

14. Event-by-Event Fluctuations in Particle Multiplicities and Transverse Energy Produced in 158.A GeV Pb+Pb collisions

Author

Aggarwal, M.M., Angelis, A.L.S., Ahammed, Z., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bucher, D., Busching, H., Carlen, L., Chattopadhyay, S., Decowski, M.P., Delagrange, H., Donni, P., Dutta Majumdar, M.R., El Chenawi, K., Dubey, A.K., Enosawa, K., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Karadjev, K., Karpio, K., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Kugler, A., Kulinich, P., Kurata, M., Lebedev, A., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Miake, Y., Mishra, G.C., Mohanty, B., Mora, M.J., Morrison, D., Mukhanova, T., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Oskarsson, A., Otterlund, I., Peitzmann, T., Peressounko, D., Petracek, V., Phatak, S.C., Pinganaud, W., Plasil, F., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Sumbera, M., Svensson, T., Tsvetkov, A., Tykarski, L., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., and Young, G.R.

Subjects
Nuclear Physics
Abstract

Event-by-event fluctuations in the multiplicities of charged particles and photons, and the total transverse energy in 158$\cdot A$ GeV Pb+Pb collisions are studied for a wide range of centralities. For narrow centrality bins the multiplicity and transverse energy distributions are found to be near perfect Gaussians. The effect of detector acceptance on the multiplicity fluctuations has been studied and demonstrated to follow statistical considerations. The centrality dependence of the charged particle multiplicity fluctuations in the measured data has been found to agree reasonably well with those obtained from a participant model. However for photons the multiplicity fluctuations has been found to be lower compared to those obtained from a participant model. The multiplicity and transverse energy fluctuations have also been compared to those obtained from the VENUS event generator.

Published
2001

15. Direct Photon Production in 158 A GeV $^{208}Pb+^{208}Pb$ collisions

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Areev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.M., Borocz, Z., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Klein-Boesing, Christian, Knoche, S., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mgebrichvili, G., Miake, Y., Mir, Md.F., Mishra, G.C., Miyamoto, Y., Mohanty, B., Morrison, Douglas R.O., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Pavliouk, S., Peitzmann, T., Petracek, V., Pinganaud, W., Plasil, F., von Poblotzki, U., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sood, G., Srensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
High Energy Physics::Experiment, Nuclear Physics - Experiment, Nuclear Experiment
Abstract

A measurement of direct photon production in 208Pb + 208Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield or upper limit of direct photons as a function of transverse momentum in the interval 0.5 < p_T < 4 GeV/c is presented. A significant direct photon excess is observed at p_T > 1.5 GeV/c in central collisions. The results are compared to proton-induced results and to theoretical predictions. Implications for the dynamics of high-energy heavy-ion collisions are discussed. A measurement of direct photon production in 208Pb + 208Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield or upper limit of direct photons as a function of transverse momentum in the interval 0.5 < p_T < 4 GeV/c is presented. A significant direct photon excess is observed at p_T > 1.5 GeV/c in central collisions. The results are compared to proton-induced results and to theoretical predictions. Implications for the dynamics of high-energy heavy-ion collisions are discussed.

Published
2001

16. Three-pion interferometry results from central Pb plus Pb collisions at 158A GeV/c

Author

Aggarwal, M M, Agnihotri, A, Ahammed, Z, Angelis, A L S, Antonenko, V, Arefiev, V, Astakhov, V, Avdeitchikov, V, Awes, T C, Baba, P V K S, Badyal, S K, Barlag, C, Bathe, S, Batiounia, B, Bernier, T, Bhalla, K B, Bhatia, VS, Blume, C, Bock, R, Bohne, E M, Borocz, Z, Bucher, D, Buijs, A, Busching, H, Carlen, L, Chalyshev, V, Chattopadhyay, S, Cherbatchev, R, Chujo, T, Claussen, A, Das, A C, Decowski, M P, Delagrange, H, Djordjadze, V, Donni, P, Doubovik, I, Dutt, S, Majumdar, M R D, El Chenawi, K, Eliseev, S, Enosawa, K, Foka, P, Fokin, S, Ganti, M S, Garpman, S, Gavrishchuk, O, Geurts, F J M, Ghosh, T K, Glasow, R, Gupta, S K, Guskov, B, Gustafsson, H.A., Gutbrod, H H, Higuchi, R, Hrivnacova, I, Ippolitov, M, Kalechofsky, H, Kamermans, R, Kampert, K H, Karadjev, K, Karpio, K, Kato, S, Kees, S, Klein-Bosing, C, Knoche, S, Kolb, B W, Kosarev, I, Koutcheryaev, I, Krumpel, T, Kugler, A, Kulinich, P, Kurata, M, Kurita, K, Kuzmin, N, Langbein, I, Lebedev, A, Lee, Y Y, Lohner, H, Luquin, L, Mahapatra, D P, Manko, V, Martin, M, Martinez, G, Maximov, A, Mgebrichvili, G, Miake, Y, Mir, M F, Mishra, G C, Miyamoto, Y, Mohanty, B, Mora, M J, Morrison, D, Mukhopadhyay, D S, Naef, H, Nandi, B K, Nayak, S K, Nayak, T K, Neumaier, S, Nianine, A, Nikitine, V, Nikolaev, S, Nilsson, P, Nishimura, S, Nomokonov, P, Nystrand, J, Obenshain, F E, Oskarsson, A, Otterlund, I, Pachr, M, Pavliouk, S, Peitzmann, T, Petracek, V, Pinganaud, W, Plasil, F, von Poblotzki, U, Purschke, M L, Rak, J, Raniwala, R, Raniwala, S, Ramamurthy, V S, Rao, N K, Retiere, F, Reygers, K, Roland, G, Rosselet, L, Roufanov, I, Roy, C, Rubio, J M, Sako, H, Sambyal, SS, Santo, R, Sato, S, Schlagheck, H, Schutz, Y, Shabratova, G, Shah, T H, Sibiriak, I, Siemiarczuk, T, Silvermyr, D, Sinha, BC, Slavine, N, Soderstrom, K, Solomey, N, Sorensen, S P, Stankus, P, Stefanek, G, Steinberg, P, Stenlund, E, Stuken, D, Sumbera, M, Svensson, T, Trivedi, M D, Tsvetkov, A., Tykarski, L, Urbahn, J, van der Pijll, E C, van Eijndhoven, N, van Nieuwenhuizen, G J, Vinogradov, A, Viyogi, Y P, Vodopianov, A, Voros, S, Wyslouch, B, Yagi, K, Yokota, Y, Young, GR, KVI - Center for Advanced Radiation Technology, and Research unit Nuclear & Hadron Physics

Subjects
MODEL, TRACKING, MULTISTEP AVALANCHE CHAMBER, HEAVY-ION COLLISIONS, PERFORMANCE, Nuclear Experiment, PB+PB COLLISIONS, 3-PION CORRELATIONS
Abstract

Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb + Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

Published
2000

17. Scaling of Particle and Transverse Energy Production in 208Pb+208Pb collisions at 158 A GeV

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Baldine, A., Barabach, L., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bohne, E.M., Borocz, Z.K., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Kim, H., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mehdiyev, Rashid R., Mgebrichvili, G., Miake, Y., Mikhalev, D., Mir, Md.F., Mishra, G.C., Miyamoto, Y., Mohanty, B., Mora, M.J., Morrison, Douglas R.O., Mukhopadhyay, D.S., Myalkovski, V., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Parfenov, A., Pavliouk, S., Peitzmann, T., Petracek, V., Plasil, F., Pinganaud, W., Purschke, M.L., Raeven, B., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., van de Pijll, E.C., van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., Young, G.R., KVI - Center for Advanced Radiation Technology, and Research unit Nuclear & Hadron Physics

Subjects
Physics and Astronomy (miscellaneous), Nuclear Theory, FOS: Physical sciences, HEAVY-ION COLLISIONS, Nuclear physics, TARGETS, DISTRIBUTIONS, Nuclear Physics - Experiment, Physics::Chemical Physics, Nuclear Experiment (nucl-ex), Nuclear Experiment, Engineering (miscellaneous), Scaling, Physics, Range (particle radiation), PLASMA, NUCLEUS-NUCLEUS COLLISIONS, HADRONS, MULTIPLICITY, Charged particle, MOMENTUM, MODEL, Pseudorapidity, ULTRARELATIVISTIC ENERGIES, Production (computer science), High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Impact parameter, Nucleon, Energy (signal processing)
Abstract

Transverse energy, charged particle pseudorapidity distributions and photon transverse momentum spectra have been studied as a function of the number of participants (N_{part}) and the number of binary nucleon-nucleon collisions (N_{coll}) in 158 A GeV Pb+Pb collisions over a wide impact parameter range. A scaling of the transverse energy pseudorapidity density at midrapidity as N_{part}^{1.08 \pm 0.06} and N_{coll}^{0.83 \pm 0.05} is observed. For the charged particle pseudorapidity density at midrapidity we find a scaling as N_{part}^{1.07 \pm 0.04} and N_{coll}^{0.82 \pm 0.03}. This faster than linear scaling with N_{part} indicates a violation of the naive Wounded Nucleon Model., 13 pages, 16 figures, submitted to European Physical Journal C (revised results for scaling exponents)

Published
2000

18. Three-pion interferometry results from central Pb + Pb collisions at 158 A GeV/c

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.-M., Borocz, Z., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.-H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Klein-Bosing, C., Knoche, S., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mgebrichvili, G., Miake, Y., Mir, Md.F., Mishra, G.C., Miyamoto, Y., Mohanty, B., Mora, M.-J., Morrison, D., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Naya, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Pavliouk, S., Peitzmann, T., Petracek, V., Pinganaud, W., Plasil, F., von Poblotzki, U., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., Pijll, E.C.v.d., Eijndhoven, N.v., Nieuwenhuizen, G.J.v., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
Physics
Published
2000

19. Three-Pion Interferometry Results from Central Pb+Pb Collisions at 158 A GeV/c

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.-M., Borocz, Z., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.-H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Klein-Bosing, C., Knoche, S., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mgebrichvili, G., Miake, Y., Mir, Md.F., Mishra, G.C., Miyamoto, Y., Mohanty, B., Mora, M.-J., Morrison, D., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Pavliouk, S., Peitzmann, T., Petracek, V., Pinganaud, W., Plasil, F., von Poblotzki, U., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., Pijll, E.C.v.d., Eijndhoven, N.v., Nieuwenhuizen, G.J.v., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment, Particle Physics - Experiment
Abstract

Three-particle correlations have been measured for identified negative pions from central 158 A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source. Three-particle correlations have been measured for identified negative pions from central 158 A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

Published
2000

20. Observation of Direct Photons in Central 158 A GeV $^{208}Pb+^{208}Pb$ Collisions

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.-M., Borocz, Z., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.-H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Klein-Bosing, C., Knoche, S., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mgebrichvili, G., Miake, Y., Mir, Md.F., Mishra, G.C., Miyamoto, Y., Mohanty, B., Mora, M.-J., Morrison, D., Mukhopadhyay, D.S., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Pavliouk, S., Peitzmann, T., Petracek, V., Pinganaud, W., Plasil, F., Poblotzki, U.v., Purschke, M.L., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sood, G., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., Pijll, E.C.v.d., Eijndhoven, N.v., Nieuwenhuizen, G.J.v., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
High Energy Physics::Experiment, Nuclear Physics - Experiment, Nuclear Experiment
Abstract

A measurement of direct photon production in 208Pb + 208Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central collisions is extracted as a function of transverse momentum in the interval 0.5 < p_T < 4 GeV/c. A significant direct photon signal, compared to statistical and systematical errors, is seen at p_T > 1.5 GeV/c. The results constitute the first observation of direct photons in ultrarelativistic heavy-ion collisions which could be significant for diagnosis of quark gluon plasma formation. A measurement of direct photon production in 208Pb + 208Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central collisions is extracted as a function of transverse momentum in the interval 0.5 < p_T < 4 GeV/c. A significant direct photon signal, compared to statistical and systematical errors, is seen at p_T > 1.5 GeV/c. The results constitute the first observation of direct photons in ultrarelativistic heavy-ion collisions which could be significant for diagnosis of quark gluon plasma formation.

Published
2000

21. Freeze-out parameters in central 158A (GeVPb)-Pb-208+Pbcollisions

Author

Aggarwal, M M, Agnihotri, A, Ahammed, Z, Angelis, A L S, Antonenko, V, Arefiev, V, Astakhov, V, Avdeitchikov, V, Awes, T C, Baba, P V K S, Badyal, S K, Baldine, A, Barabach, L, Barlag, C, Bathe, S, Batiounia, B, Bernier, T, Bhalla, K B, Bhatia, V S, Blume, C, Bock, R, Bohne, E M, Borocz, Z K, Bucher, D, Buijs, A, Busching, H, Carlen, L, Chalyshev, V, Chattopadhyay, S, Cherbatchev, R, Chujo, T, Claussen, A, Das, A C, Decowski, M P, Delagrange, H, Djordjadze, V, Donni, P, Doubovik, I, Dutt, S, Majumdar, M R D, El Chenawi, K, Eliseev, S, Enosawa, K, Foka, P, Fokin, S, Frolov, V, Ganti, M S, Garpman, S, Gavrishchuk, O, Geurts, F J M, Ghosh, T K, Glasow, R, Gupta, S K, Guskov, B, Gustafsson, H.A., Gutbrod, H H, Higuchi, R, Hrivnacova, I, Ippolitov, M, Kalechofsky, H, Kamermans, R, Kampert, K H, Karadjev, K, Karpio, K, Kato, S, Kees, S, Kim, H, Kolb, B W, Kosarev, I, Koutcheryaev, I, Krumpel, T, Kugler, A, Kulinich, P, Kurata, M, Kurita, K, Kuzmin, N, Langbein, I, Lebedev, A, Lee, YY, Lohner, H, Luquin, L, Mahapatra, D P, Manko, V, Martin, M, Martinez, G, Maximov, A, Mehdiyev, R, Mgebrichvili, G, Miake, Y, Mikhalev, D, Mir, M F, Mishra, G C, Miyamoto, Y, Morrison, D, Mukhopadhyay, D S, Myalkovski, V, Naef, H, Nandi, B K, Nayak, S K, Nayak, T K, Neumaier, S, Nianine, A, Nikitine, V, Nikolaev, S, Nilsson, P, Nishimura, S, Nomokonov, P, Nystrand, J, Obenshain, F E, Oskarsson, A, Otterlund, I, Pachr, M, Parfenov, A, Pavliouk, S, Peitzmann, T, Petracek, V, Plasil, F, Pinganaud, W, Purschke, M L, Raeven, B, Rak, J, Raniwala, R, Raniwala, S, Ramamurthy, V S, Rao, N K, Retiere, F, Reygers, K, Roland, G, Rosselet, L, Roufanov, I, Roy, C, Rubio, J M, Sako, H, Sambyal, S S, Santo, R, Sato, S, Schlagheck, H, Schutz, Y, Shabratova, G, Shah, T H, Sibiriak, I, Siemiarczuk, T, Silvermyr, D, Sinha, BC, Slavine, N, Soderstrom, K, Solomey, N, Sorensen, S P, Stankus, P, Stefanek, G, Steinberg, P, Stenlund, E, Stuken, D, Sumbera, M, Svensson, T, Trivedi, M D, Tsvetkov, A., Tykarski, L, Urbahn, J, von der Pijll, E C, von Eijndhoven, N, von Nieuwenhuizen, G J, Vinogradov, A, Viyogi, Y P, Vodopianov, A, Voros, S, Wyslouch, B, Yagi, K, Yokota, Y, Young, G R, KVI - Center for Advanced Radiation Technology, and Research unit Nuclear & Hadron Physics

Subjects
Nuclear Theory, NUCLEAR COLLISIONS, EXPANSION, HEAVY-ION COLLISIONS, Nuclear Experiment
Abstract

Neutral pion production in central 158A GeV Pb-208 + Pb-208 collisions has been studied in the WA98 experiment at the CERN Super Proton Synchrotron. The pi(0) transverse mass spectrum has been analyzed in terms of a thermal model with hydrodynamic expansion. The high accuracy and large kinematic coverage of the measurement allow one to limit previously noted ambiguities in the extracted freeze-out parameters. The results are shown to be sensitive to the shape of the velocity distribution at freeze-out.

Published
1999

22. Freeze-Out Parameters in Central 158 AGeV $^{208}Pb$ + $^{208}Pb$ Collisions

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Baldine, A., Barabach, L., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.-M., Borocz, Z.K., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Delagrange, H., Djordjadze, V., Donni, P., Doubovik, I., Dutt, S., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.-H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Kim, H., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Martinez, G., Maximov, A., Mehdiyev, R., Mgebrichvili, G., Miake, Y., Mikhalev, D., Mir, Md.F., Mishra, G.C., Miyamoto, Y., Morrison, D., Mukhopadhyay, D.S., Myalkovski, V., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Parfenov, A., Pavliouk, S., Peitzmann, T., Petracek, V., Plasil, F., Pinganaud, W., Purschke, M.L., Raeven, B., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Schutz, Y., Shabratova, G., Shah, T.H., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Tykarski, L., Urbahn, J., v.d.Pijll, E.C., v.Eijndhoven, N., v.Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
Nuclear Theory, High Energy Physics::Experiment, Nuclear Physics - Experiment, Nuclear Experiment
Abstract

Neutral pion production in central 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. The pi0 transverse mass spectrum has been analyzed in terms of a thermal model with hydrodynamic expansion. The high accuracy and large kinematic coverage of the measurement allow to limit previously noted ambiguities in the extracted freeze-out parameters. The results are shown to be sensitive to the shape of the velocity distribution at freeze-out. Neutral pion production in central 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. The pi0 transverse mass spectrum has been analyzed in terms of a thermal model with hydrodynamic expansion. The high accuracy and large kinematic coverage of the measurement allow to limit previously noted ambiguities in the extracted freeze-out parameters. The results are shown to be sensitive to the shape of the velocity distribution at freeze-out.

Published
1999

23. Centrality dependence of neutral pion production in 158A GeV Pb-208+Pb-208 collisions

Author

Aggarwal, MM, Agnihotri, A, Ahammed, Z, Angelis, ALS, Antonenko, [No Value], Arefiev, [No Value], Astakhov, [No Value], Avdeitchikov, [No Value], Awes, TC, Baba, PVKS, Badyal, SK, Baldine, A, Barabach, L, Barlag, C, Bathe, S, Batiounia, B, Bernier, T, Bhalla, KB, Bhatia, VS, Blume, C, Bock, R, Bohne, EM, Borocz, ZK, Bucher, D, Buijs, A, Busching, H, Carlen, L, Chalyshev, [No Value], Chattopadhyay, S, Cherbatchev, R, Chujo, T, Claussen, A, Das, AC, Decowski, MP, Djordjadze, [No Value], Donni, P, Doubovik, [No Value], Majumdar, MRD, El Chenawi, K, Eliseev, S, Enosawa, K, Foka, P, Fokin, S, Frolov, [No Value], Ganti, MS, Garpman, S, Gavrishchuk, O, Geurts, FJM, Ghosh, TK, Glasow, R, Gupta, SK, Guskov, B, Gustafsson, H.-A., Gutbrod, HH, Higuchi, R, Hrivnacova, [No Value], Ippolitov, M, Kalechofsky, H, Kamermans, R, Kampert, KH, Karadjev, K, Karpio, K, Kato, S, Kees, S, Kim, H, Kolb, BW, Kosarev, [No Value], Koutcheryaev, [No Value], Krumpel, T, Kugler, A, Kulinich, P, Kurata, M, Kurita, K, Kuzmin, N, Langbein, [No Value], Lebedev, A, Lee, YY, Lohner, H, Luquin, L, Mahapatra, DP, Manko, [No Value], Martin, M, Maximov, A, Mehdiyev, R, Mgebrichvili, G, Miake, Y, Mikhalev, D, Mishra, GC, Miyamoto, Y, Morrison, D, Mukhopadhyay, DS, Myalkovski, [No Value], Naef, H, Nandi, BK, Nayak, SK, Nayak, TK, Neumaier, S, Nianine, A, Nikitine, [No Value], Nikolaev, S, Nilsson, P, Nishimura, S, Nomokonov, P, Nystrand, J, Obenshain, FE, Oskarsson, A, Otterlund, [No Value], Pachr, M, Parfenov, A, Pavliouk, S, Pietzmann, T, Patracek, [No Value], Pinanaud, W, Plasil, F, Purschke, ML, Raeven, B, Rak, J, Raniwala, R, Raniwala, S, Ramamurthy, VS, Rao, NK, Retiere, F, Reygers, K, Roland, G, Rosselet, L, Roufanov, [No Value], Roy, C, Rubio, JM, Sako, H, Sambyal, SS, Santo, R, Sato, S, Schlagheck, H, Shabratova, G, Sibiriak, [No Value], Siemiarczuk, T, Silvermyr, D, Sinha, BC, Slavine, N, Soderstrom, K, Solomey, N, Sorensen, SP, Stankus, P, Stefanek, G, Steinberg, P, Stenlund, E, Stuken, D, Sumbera, M, Svensson, T, Trivedi, MD, Tsvetkov, A., Twenhofel, C, Tykarski, L, Urbahn, J, von Eijndhoven, N, von Nieuwenhuizen, GJ, Vinogradov, A, Viyogi, YP, Vodopianov, A, Voros, S, Wyslouch, B, Yagi, K, Yokota, Y, Young, GR, and KVI - Center for Advanced Radiation Technology

Subjects
HADRONIC COLLISIONS, MODEL, CHARGED-PARTICLES, ENERGIES, Nuclear Theory, MULTIPLICITY DEPENDENCE, DISTRIBUTIONS, NUCLEUS COLLISIONS, Nuclear Experiment, TRANSVERSE-MOMENTUM SPECTRA, P-NUCLEUS
Abstract

The production of neutral pions in 158A GeV Pb-208 + Pb-208 collisions has been studied in the WA98 experiment at the CERN Super Proton Synchrotron (SPS). Transverse momentum spectra are studied for the range 0.3 less than or equal to m(T) - m(0) less than or equal to 4.0 GeV/c. The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons. This is most naturally explained by assuming an equilibrated system. [S0031-9007(98)07532-2].

Published
1998

24. Directed Flow in 158 A GeV $^{208}Pb$ + $^{208}Pb$ Collisions

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Baldine, A., Barabach, L., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.M., Borocz, Z., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Dzhordzhadze, V., Donni, P., Doubovik, I., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.H., Karadzhev, K., Karpio, K., Kato, S., Kees, S., Kim, H., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Maximov, A., Mehdiyev, Rashid R., Mgebrichvili, G., Miake, Y., Mikhalev, D., Mishra, G.C., Miyamoto, Y., Morrison, Douglas R.O., Mukhopadhyay, D.S., Myalkovsky, V., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitin, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Parfenov, A., Pavliouk, S., Peitzmann, T., Petracek, V., Plasil, F., Pinanaud, W., Purschke, M.L., Raven, B., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.R., Shabratova, G., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavin, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Twenhofel, C., Tykarski, L., Urbahn, J., Van Eijndhoven, N., van Nieuwenhuizen, G.J., Vinogradov, A., Viyogi, Y.P., Vodopianov, A.S., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
Nuclear Theory, Nuclear Physics - Experiment, Nuclear Experiment
Abstract

The directed flow of protons and positive pions have been studied in 158 A GeV Pb + Pb collisions. A directed flow analysis of the rapidity dependence of the average transverse momentum projected onto the reaction plane is presented for semi-central collisions with impact parameters of approximately 8 fm, where the flow effect is largest. The magnitude of the directed flow is found to be significantly smaller than observed at AGS energies and than RQMD model predictions. The directed flow of protons and positive pions have been studied in 158 A GeV Pb + Pb collisions. A directed flow analysis of the rapidity dependence of the average transverse momentum projected onto the reaction plane is presented for semi-central collisions with impact parameters of approximately 8 fm, where the flow effect is largest. The magnitude of the directed flow is found to be significantly smaller than observed at AGS energies and than RQMD model predictions. The directed flow of protons and positive pions have been studied in 158 A GeV Pb + Pb collisions. A directed flow analysis of the rapidity dependence of the average transverse momentum projected onto the reaction plane is presented for semi-central collisions with impact parameters of approximately 8 fm, where the flow effect is largest. The magnitude of the directed flow is found to be significantly smaller than observed at AGS energies and than RQMD model predictions.

Published
1998

25. Centrality Dependence of Neutral Pion Production in 158 A GeV $^{208}Pb +^{208}Pb$ Collisions

Author

Aggarwal, M.M., Agnihotri, A., Ahammed, Z., Angelis, A.L.S., Antonenko, V., Arefiev, V., Astakhov, V., Avdeitchikov, V., Awes, T.C., Baba, P.V.K.S., Badyal, S.K., Baldine, A., Barabach, L., Barlag, C., Bathe, S., Batiounia, B., Bernier, T., Bhalla, K.B., Bhatia, V.S., Blume, C., Bock, R., Bohne, E.-M., Borocz, Z.K., Bucher, D., Buijs, A., Busching, H., Carlen, L., Chalyshev, V., Chattopadhyay, S., Cherbatchev, R., Chujo, T., Claussen, A., Das, A.C., Decowski, M.P., Djordjadze, V., Donni, P., Doubovik, I., Dutta Majumdar, M.R., El Chenawi, K., Eliseev, S., Enosawa, K., Foka, P., Fokin, S., Frolov, V., Ganti, M.S., Garpman, S., Gavrishchuk, O., Geurts, F.J.M., Ghosh, T.K., Glasow, R., Gupta, S.K., Guskov, B., Gustafsson, H.A., Gutbrod, H.H., Higuchi, R., Hrivnacova, I., Ippolitov, M., Kalechofsky, H., Kamermans, R., Kampert, K.-H., Karadjev, K., Karpio, K., Kato, S., Kees, S., Kim, H., Kolb, B.W., Kosarev, I., Koutcheryaev, I., Krumpel, T., Kugler, A., Kulinich, P., Kurata, M., Kurita, K., Kuzmin, N., Langbein, I., Lebedev, A., Lee, Y.Y., Lohner, H., Luquin, L., Mahapatra, D.P., Manko, V., Martin, M., Maximov, A., Mehdiyev, R., Mgebrichvili, G., Miake, Y., Mikhalev, D., Mishra, G.C., Miyamoto, Y., Morrison, D., Mukhopadhyay, D.S., Myalkovski, V., Naef, H., Nandi, B.K., Nayak, S.K., Nayak, T.K., Neumaier, S., Nianine, A., Nikitine, V., Nikolaev, S., Nilsson, P., Nishimura, S., Nomokonov, P., Nystrand, J., Obenshain, F.E., Oskarsson, A., Otterlund, I., Pachr, M., Parfenov, A., Pavliouk, S., Pietzmann, T., Patracek, V., Pinanaud, W., Plasil, F., Purschke, M.L., Raeven, B., Rak, J., Raniwala, R., Raniwala, S., Ramamurthy, V.S., Rao, N.K., Retiere, F., Reygers, K., Roland, G., Rosselet, L., Roufanov, I., Roy, C., Rubio, J.M., Sako, H., Sambyal, S.S., Santo, R., Sato, S., Schlagheck, H., Schmidt, H.-R., Shabratova, G., Sibiriak, I., Siemiarczuk, T., Silvermyr, D., Sinha, B.C., Slavine, N., Soderstrom, K., Solomey, N., Sorensen, S.P., Stankus, P., Stefanek, G., Steinberg, P., Stenlund, E., Stuken, D., Sumbera, M., Svensson, T., Trivedi, M.D., Tsvetkov, A., Twenhofel, C., Tykarski, L., Urbahn, J., Eijndhoven, N.v., Nieuwenhuizen, G.J.v., Vinogradov, A., Viyogi, Y.P., Vodopianov, A., Voros, S., Wyslouch, B., Yagi, K., Yokota, Y., and Young, G.R.

Subjects
Nuclear Theory, High Energy Physics::Experiment, Nuclear Physics - Experiment, Nuclear Experiment
Abstract

The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c < mT-m0 < 4.0 GeV/c. The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system. The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c < mT-m0 < 4.0 GeV/c. The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system. The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c < mT-m0 < 4.0 GeV/c. The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system.

Published
1998

37. Absolute coronary artery calcium scores are superior to MESA percentile rank in predicting obstructive coronary artery disease.

Author

Akram K, Voros S, Akram, Kamran, and Voros, Szilard

Abstract

Background: Coronary artery calcium scoring (CAC) is an excellent non-invasive method to evaluate coronary atherosclerotic burden. To better predict the risk of future events in an individual, their absolute CAC score is compared to an age- and gender-matched cohort in order to assign a percentile rank. However, it is unknown whether absolute CAC or percentile rank is better in predicting obstructive coronary artery disease (CAD). We hypothesized that absolute CAC is superior to percentile rank in predicting obstructive CAD.Methods: 210 consecutive patients referred to our institution for CAC and coronary artery computed tomography angiography (CTA) were included. CAC scores were expressed as Agatston score; percentile rank as published by the Multi-Ethnic Study of Atherosclerosis. Coronary artery stenoses were graded semi-quantitatively. Receiver operating characteristics curves (ROC) were used to assess the performance of CAC to predict obstructive CAD.Results: In the overall group, the area under the curve (AUC) was significantly greater for absolute CAC compared to MESA percentile rank in predicting obstructive CAD (0.80 vs. 0.72, P = 0.006). Subgroup analysis revealed similar findings: AUC for absolute CAC was greater than for MESA percentile rank in males (0.82 vs. 0.71, P = 0.008), females (0.78 vs. 0.72, P = 0.085), symptomatic patients (0.78 vs. 0.72, P = 0.067) and in asymptomatic subjects (0.89 vs. 0.74, P = 0.05).Conclusion: Absolute CAC is superior to MESA percentile rank in predicting obstructive CAD. This finding was seen in both symptomatic and asymptomatic patients as well as in males and females. [ABSTRACT FROM AUTHOR]

Published
2008
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43. Development of a blood-based gene expression algorithm for assessment of obstructive coronary artery disease in non-diabetic patients

Author

Ellis Stephen G, Schwartz Robert S, Ginsburg Geoffrey S, Kraus William E, Voros Szilard, Rosenberg Steven, Tingley Whittemore G, Daniels Susan E, Beineke Philip, Wingrove James A, Elashoff Michael R, Tahirkheli Naheem, Waksman Ron, McPherson John, Lansky Alexandra J, and Topol Eric J

Subjects
Atherosclerosis, gene expression, whole blood classifier, Internal medicine, RC31-1245, Genetics, QH426-470
Abstract

Abstract Background Alterations in gene expression in peripheral blood cells have been shown to be sensitive to the presence and extent of coronary artery disease (CAD). A non-invasive blood test that could reliably assess obstructive CAD likelihood would have diagnostic utility. Results Microarray analysis of RNA samples from a 195 patient Duke CATHGEN registry case:control cohort yielded 2,438 genes with significant CAD association (p < 0.05), and identified the clinical/demographic factors with the largest effects on gene expression as age, sex, and diabetic status. RT-PCR analysis of 88 CAD classifier genes confirmed that diabetic status was the largest clinical factor affecting CAD associated gene expression changes. A second microarray cohort analysis limited to non-diabetics from the multi-center PREDICT study (198 patients; 99 case: control pairs matched for age and sex) evaluated gene expression, clinical, and cell population predictors of CAD and yielded 5,935 CAD genes (p < 0.05) with an intersection of 655 genes with the CATHGEN results. Biological pathway (gene ontology and literature) and statistical analyses (hierarchical clustering and logistic regression) were used in combination to select 113 genes for RT-PCR analysis including CAD classifiers, cell-type specific markers, and normalization genes. RT-PCR analysis of these 113 genes in a PREDICT cohort of 640 non-diabetic subject samples was used for algorithm development. Gene expression correlations identified clusters of CAD classifier genes which were reduced to meta-genes using LASSO. The final classifier for assessment of obstructive CAD was derived by Ridge Regression and contained sex-specific age functions and 6 meta-gene terms, comprising 23 genes. This algorithm showed a cross-validated estimated AUC = 0.77 (95% CI 0.73-0.81) in ROC analysis. Conclusions We have developed a whole blood classifier based on gene expression, age and sex for the assessment of obstructive CAD in non-diabetic patients from a combination of microarray and RT-PCR data derived from studies of patients clinically indicated for invasive angiography. Clinical trial registration information PREDICT, Personalized Risk Evaluation and Diagnosis in the Coronary Tree, http://www.clinicaltrials.gov, NCT00500617

Published
2011
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45. Patient management after noninvasive cardiac imaging results from SPARC (Study of myocardial perfusion and coronary anatomy imaging roles in coronary artery disease).

Author

Hachamovitch R, Nutter B, Hlatky MA, Shaw LJ, Ridner ML, Dorbala S, Beanlands RS, Chow BJ, Branscomb E, Chareonthaitawee P, Weigold WG, Voros S, Abbara S, Yasuda T, Jacobs JE, Lesser J, Berman DS, Thomson LE, Raman S, and Heller GV

Abstract

Objectives: This study examined short-term cardiac catheterization rates and medication changes after cardiac imaging.Background: Noninvasive cardiac imaging is widely used in coronary artery disease, but its effects on subsequent patient management are unclear.Methods: We assessed the 90-day post-test rates of catheterization and medication changes in a prospective registry of 1,703 patients without a documented history of coronary artery disease and an intermediate to high likelihood of coronary artery disease undergoing cardiac single-photon emission computed tomography, positron emission tomography, or 64-slice coronary computed tomography angiography.Results: Baseline medication use was relatively infrequent. At 90 days, 9.6% of patients underwent catheterization. The rates of catheterization and medication changes increased in proportion to test abnormality findings. Among patients with the most severe test result findings, 38% to 61% were not referred to catheterization, 20% to 30% were not receiving aspirin, 35% to 44% were not receiving a beta-blocker, and 20% to 25% were not receiving a lipid-lowering agent at 90 days after the index test. Risk-adjusted analyses revealed that compared with stress single-photon emission computed tomography or positron emission tomography, changes in aspirin and lipid-lowering agent use was greater after computed tomography angiography, as was the 90-day catheterization referral rate in the setting of normal/nonobstructive and mildly abnormal test results.Conclusions: Overall, noninvasive testing had only a modest impact on clinical management of patients referred for clinical testing. Although post-imaging use of cardiac catheterization and medical therapy increased in proportion to the degree of abnormality findings, the frequency of catheterization and medication change suggests possible undertreatment of higher risk patients. Patients were more likely to undergo cardiac catheterization after computed tomography angiography than after single-photon emission computed tomography or positron emission tomography after normal/nonobstructive and mildly abnormal study findings. (Study of Perfusion and Anatomy's Role in Coronary Artery [CAD] [SPARC]; NCT00321399). [ABSTRACT FROM AUTHOR]

Published
2012
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48. Impact of Relative Volume Difference Between Magnetic Resonance Imaging and Three-dimensional Transrectal Ultrasound Segmentation on Clinically Significant Prostate Cancer Detection in Fusion Magnetic Resonance Imaging-targeted Biopsy.

Author

Lenfant L, Beitone C, Troccaz J, Beaugerie A, Rouprêt M, Seisen T, Renard-Penna R, Voros S, and Mozer PC

Subjects
Humans, Male, Aged, Middle Aged, Ultrasonography, Interventional methods, Prostate pathology, Prostate diagnostic imaging, Retrospective Studies, Ultrasonography methods, Magnetic Resonance Imaging, Interventional methods, Prostatic Neoplasms diagnostic imaging, Prostatic Neoplasms pathology, Image-Guided Biopsy methods, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging methods
Abstract

Background: Segmentation of three-dimensional (3D) transrectal ultrasound (TRUS) images is known to be challenging, and the clinician often lacks a reliable and easy-to-use indicator to assess its accuracy during the fusion magnetic resonance imaging (MRI)-targeted prostate biopsy procedure., Objective: To assess the effect of the relative volume difference between 3D-TRUS and MRI segmentation on the outcome of a targeted biopsy., Design, Setting, and Participants: All adult males who underwent an MRI-targeted prostate biopsy for clinically suspected prostate cancer between February 2012 and July 2021 were consecutively included., Intervention: All patients underwent a fusion MRI-targeted prostate biopsy with a Koelis device., Outcome Measurements and Statistical Analysis: Three-dimensional TRUS and MRI prostate volumes were calculated using 3D prostate models issued from the segmentations. The primary outcome was the relative segmentation volume difference (SVD) between transrectal ultrasound and MRI divided by the MRI volume (SVD = MRI volume - TRUS volume/MRI volume) and its correlation with clinically significant prostate cancer (eg, International Society of Urological Pathology [ISUP] ≥2) positiveness on targeted biopsy cores., Results and Limitations: Overall, 1721 patients underwent a targeted biopsy resulting in a total of 5593 targeted cores. The median relative SVD was significantly lower in patients diagnosed with clinically significant prostate cancer than in those with ISUP 0-1: (6.7% [interquartile range {IQR} -2.7, 13.6] vs 8.0% [IQR 3.3, 16.4], p < 0.01). A multivariate regression analysis showed that a relative SVD of >10% of the MRI volume was associated with a lower detection rate of clinically significant prostate cancer (odds ratio = 0.74 [95% confidence interval: 0.55-0.98]; p = 0.038)., Conclusions: A relative SVD of >10% of the MRI segmented volume was associated with a lower detection rate of clinically significant prostate cancer on targeted biopsy cores. The relative SVD can be used as a per-procedure quality indicator of 3D-TRUS segmentation., Patient Summary: A discrepancy of ≥10% between segmented magnetic resonance imaging and transrectal ultrasound volume is associated with a reduced ability to detect significant prostate cancer on targeted biopsy cores., (Copyright © 2023. Published by Elsevier B.V.)

Published
2024
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49. Learning curve for fusion magnetic resonance imaging targeted prostate biopsy and three-dimensional transrectal ultrasonography segmentation.

Author

Lenfant L, Beitone C, Troccaz J, Rouprêt M, Seisen T, Voros S, and Mozer PC

Subjects
Humans, Male, Aged, Middle Aged, Ultrasonography, Interventional methods, Imaging, Three-Dimensional, Magnetic Resonance Imaging, Magnetic Resonance Imaging, Interventional, Clinical Competence, Retrospective Studies, Learning Curve, Prostatic Neoplasms pathology, Prostatic Neoplasms diagnostic imaging, Image-Guided Biopsy methods, Prostate pathology, Prostate diagnostic imaging
Abstract

Objective: To report the learning curve of multiple operators for fusion magnetic resonance imaging (MRI) targeted biopsy and to determine the number of cases needed to achieve proficiency., Materials and Methods: All adult males who underwent fusion MRI targeted biopsy between February 2012 and July 2021 for clinically suspected prostate cancer (PCa) in a single centre were included. Fusion transrectal MRI targeted biopsy was performed under local anaesthesia using the Koelis platform. Learning curves for segmentation of transrectal ultrasonography (TRUS) images and the overall MRI targeted biopsy procedure were estimated with locally weighted scatterplot smoothing by computing each operator's timestamps for consecutive procedures. Non-risk-adjusted cumulative sum (CUSUM) methods were used to create learning curves for clinically significant (i.e., International Society of Urological Pathology grade ≥ 2) PCa detection., Results: Overall, 1721 patients underwent MRI targeted biopsy in our centre during the study period. The median (interquartile range) times for TRUS segmentation and for the MRI targeted biopsy procedure were 4.5 (3.5, 6.0) min and 13.2 (10.6, 16.9) min, respectively. Among the 14 operators with experience of more than 50 cases, a plateau was reached after 40 cases for TRUS segmentation time and 50 cases for overall MRI targeted biopsy procedure time. CUSUM analysis showed that the learning curve for clinically significant PCa detection required 25 to 45 procedures to achieve clinical proficiency. Pain scores ranged between 0 and 1 for 84% of patients, and a plateau phase was reached after 20 to 100 cases., Conclusions: A minimum of 50 cases of MRI targeted biopsy are necessary to achieve clinical and technical proficiency and to reach reproducibility in terms of timing, clinically significant PCa detection, and pain., (© 2024 BJU International.)

Published
2024
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50. Marker-based C-arm self-calibration with unknown calibration pattern.

Author

Pivot O, Voros S, Chappard C, Bernard G, Grondin Y, and Desbat L

Subjects
Calibration, Phantoms, Imaging, Humans, Tomography, X-Ray Computed, Image Processing, Computer-Assisted methods
Abstract

Background: Accurate tomographic reconstructions require the knowledge of the actual acquisition geometry. Many mobile C-arm CT scanners have poorly reproducible acquisition geometries and thus need acquisition-specific calibration procedures. Most of geometric self-calibration methods based on projection data either need prior information or are limited to the estimation of a low number of geometric calibration parameters. Other self-calibration methods generally use a calibration pattern with known geometry and are hardly implementable in practice for clinical applications., Purpose: We present a three-step marker based self-calibration method which does not require the prior knowledge of the calibration pattern and thus enables the use of calibration patterns with arbitrary markers positions., Methods: The first step of the method aims at detecting the set of markers of the calibration pattern in each projection of the CT scan and is performed using the YOLO (You Only Look Once) Convolutional Neural Network. The projected marker trajectories are then estimated by a sequential projection-wise marker association scheme based on the Linear Assignment Problem which uses Kalman filters to predict the markers 2D positions in the projections. The acquisition geometry is finally estimated from the marker trajectories using the Bundle-adjustment algorithm., Results: The calibration method has been tested on realistic simulated images of the ICRP (International Commission on Radiological Protection) phantom, using calibration patterns with 10 and 20 markers. The backprojection error was used to evaluate the self-calibration method and exhibited sub-millimeter errors. Real images of two human knees with 10 and 30 markers calibration patterns were then used to perform a qualitative evaluation of the method, which showed a remarkable artifacts reduction and bone structures visibility improvement., Conclusions: The proposed calibration method gave promising results that pave the way to patient-specific geometric self-calibrations in clinics., (© 2024 American Association of Physicists in Medicine.)

Published
2024
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