Observation of an Exotic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>S</mml:mi><mml:mo>=</mml:mo><mml:mo>+</mml:mo><mml:mn>1</mml:mn></mml:math>Baryon in Exclusive Photoproduction from the Deuteron

Stepanyan, S.; Hicks, K.; Carman, D. S.; Pasyuk, E.; Schumacher, R. A.; Smith, E. S.; Tedeschi, D. J.; Todor, L.; Adams, G. S.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Ball, J.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Berman, B. L.; Bianchi, N.; Biselli, A.; Boiarinov, S.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, Volker; Butuceanu, C.; Calarco, J. R.; Carnahan, B.; Chen, S.; Ciciani, L.; Cole, P. L.; Coleman, Alan; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Sanctis, E. De; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Vita, R. De; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Forest, Tony A.; Funsten, H. O.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Gordon, C. I O; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R.; Hardie, J.; Heddle, D.; Heimberg, P.; Hersman, F. W.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde‐Wright, C. E.; Ito, M. M.; Jenkins, David; Joo, K. S.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, Frank; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L.; Kuang, Y.; Kubarovsky, V.; Kuhn, S. E.; Kühn, J.; Lachniet, J.; Lawrence, D.; Li, J.; Lima, A. C S; Livingston, K.; Lukashin, K.; Manak, J. J.; McAleer, S.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Muccifora, V.; Muêller, J.; Murphy, L. Y.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O’Brien, J. T.; O’Rielly, G. V.; Opper, A. K.; Osipenko, M.; Park, K.; Peterson, G. A.; Philips, S. A.; Pivnyuk, N.; Počanić, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, Barry; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, L. C.; Sober, D. I.; Strakovsky, I. I.; Stavinsky, A.; Stoler, P.; Suleiman, R.; Taiuti, M.; Taylor, S.; Thoma, U.; Thompson, R.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, Lawrence; Weller, H.R.; Weygand, D. P.; Whisnant, C. S.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.

doi:10.1103/physrevlett.91.252001

Cited by 386 publications

(135 citation statements)

References 14 publications

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“…This newly discovered hadron resonance has, given the mass and charge, an exceedingly narrow width. This feature is common with Θ + (1540), another recently reported resonance [11,12,13,14], which decays into the channel with quark content uudds and I = 0. This is believed to be the predicted [15], lowest mass, pentaquark state [16].…”

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confidence: 85%

Strange pentaquark hadrons in statistical hadronization

et al. 2003

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We study, within the statistical hadronization model, the influence of narrow strangeness carrying baryon resonances (pentaquarks) on the understanding of particle production in relativistic heavy ion collisions. There is a great variation of expected yields as function of heavy ion collision energy due to rapidly evolving chemical conditions at particle chemical freeze-out. At relatively low collision energies, these new states lead to improvement of statistical hadronization fits.PACS numbers: 24.10. Pa,13.60.Rj,12.38.Mh Enhanced production of strange hadrons in relativistic heavy ion collisions is well established [1,2]. The availability of a high abundance of strangeness favors production of strange hadron resonances, a topic of current intense experimental interest in the field of relativistic heavy ion collisions [3,4,5,6,7,8,9]. The discovery by the NA49 collaboration [10]of a new Ξ −− (1862) I = 3/2 narrow Γ < 5 MeV resonance in their pp background, rather than in the AA foreground data at projectile energy 158 GeV ( √ s NN = 17.2 GeV) poses the question in which conditions one should look in heavy ion collisions for such new resonances. This newly discovered hadron resonance has, given the mass and charge, an exceedingly narrow width. This feature is common with Θ + (1540), another recently reported resonance [11,12,13,14], which decays into the channel with quark content uudds and I = 0. This is believed to be the predicted [15], lowest mass, pentaquark state [16]. The Ξ * (1862) can be interpreted as its most massive isospin quartet member ssddū, ssudū, ssudd, ssuud with electrical charge varying, respectively, from −2 to +1, in units of |e|.Appearance of these new resonances can have many consequences in the field of heavy ion collisions. We at first explore how the introduction into the family of hadronic particles of these two new resonances, Θ + (1540) and Ξ * (1862), influence the results of statistical hadronization fit to relativistic heavy ion hadron production experimental results. We use the same data set as has been employed in Ref [2,17,18] and obtain predictions of how the relative abundances of these new resonant states vary as function of the heavy ion collision energy.Importantly, only the two already identified states with I = 0, and I = 3/2 of the anti decuplet, which also includes the I = 1/2, and I = 1 states are of relevance in the study of the statistical hadronization fits. Thus, in our analysis, we do not depend on the unknown masses of I = 1/2, and I = 1 states. However, the interpretation of the newly discovered narrow states as pentaquarks enters our considerations decisively. The pentaquark valance quark content enters the assigned chemical fugacities and phase space occupancies. The yield is proportional to the presumed spin degeneracy of the new states, taken to be two for a spin 1/2 anti decuplet.In our approach [2,17,18], as in other recent work [19], the chemical equilibrium and non-equilibrium is considered. Accordingly, we allow quark pair phase space occupancies,...

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confidence: 85%

Strange pentaquark hadrons in statistical hadronization

et al. 2003

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“…Experimental indications of the existence of Θ + [1][2][3][4][5][6][7][8][9][10][11], the first explicitly pentaquark baryon, as well negative results of the search for the Θ + [12][13][14][15], require a deep revision of our views on many aspects of phenomenology of strongly interacting particles. There also exist positive [16] and negative [15,17] reports on the search of another pentaquark member of the antidecuplet, the Ξ 3/2 , as well as a positive report on the search for an anti-charmed baryon state [18].…”

Section: Introductionmentioning

confidence: 99%

SU(3) systematization of baryons: Theoretical methods and mixing with the antidecuplet

Guzey¹,

Polyakov

2004

Ann. Phys.

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We take a fresh look at the SU(3) systematization of all known baryons with mass less than 2000 MeV. We describe well-known and new theoretical tools used in grouping elementary particles into unitary multiplets and present the emerging picture of the unitary multiplets and their mixing. The issue of multiplet mixing is discussed in detail with an emphasis on the mixing with the antidecuplet. While SU(3) does not strongly require that the antidecuplet mixes with any established octet or decuplet, it is still possible to mix the antidecuplet with a J P = 1/2 + octet. However, the mixing parameters cannot be reliably determined this way. Instead, one should consider decays of the antidecuplet members.

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“…The identified Λ(1520) tagged the strangeness of the Θ + , but the signal sat on a large and steeply-sloped background. Stronger positive evidence for a Θ + was reported by CLAS/JLab [13] in an exclusive measurement on deuterium, γd → pK + K − (n). A 4.6 to 5.8 σ signal was seen above a large background that was difficult to estimate quantitatively due to nuclear final state interaction effects.…”

Section: Experimental Evidencementioning

confidence: 73%

The Rise and Fall of Pentaquarks in Experiments

Schumacher¹

2006

AIP Conference Proceedings

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Abstract.Experimental evidence for and against the existence of pentaquarks has accumulated rapidly in the last three years. If they exist, they would be dramatic examples of hadronic states beyond our well-tested and successful particle models. The positive evidence suggests existence of baryonic objects with widths of at most a few MeV, some displaying exotic quantum numbers, such as baryons with strangeness S = +1. The non-observations of these states have often come from reaction channels very different from the positive evidence channels, making comparisons difficult. The situation has now been largely clarified, however, by high-statistics repetitions of the positive sightings, with the result that none of the positive sightings have been convincingly reproduced. The most recent unconfirmed positive sightings suffer again from low statistics and large backgrounds. It seems that a kind of "bandwagon" effect led to the overly-optimistic interpretation of numerous experiments in the earlier reports of exotic pentaquarks.

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Observation of an ExoticS=+1Baryon in Exclusive Photoproduction from the Deuteron

Cited by 386 publications

References 14 publications

Strange pentaquark hadrons in statistical hadronization

Strange pentaquark hadrons in statistical hadronization

SU(3) systematization of baryons: Theoretical methods and mixing with the antidecuplet

The Rise and Fall of Pentaquarks in Experiments

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