Search for the Theta+ pentaquark in the reaction gammad --> pK-K+n.


A search for the Theta+ in the reaction gammad --> pK-K+n was completed using the CLAS detector at Jefferson Lab. A study of the same reaction, published earlier, reported the observation of a narrow Theta+ resonance. The present experiment, with more than 30 times the integrated luminosity of our earlier measurement, does not show any evidence for a narrow pentaquark resonance. The angle-integrated upper limit on Theta+ production in the mass range of 1.52-1.56 GeV/c2 for the gammad --> pK-Theta+ reaction is 0.3 nb (95% C.L.). This upper limit depends on assumptions made for the mass and angular distribution of Theta+ production. Using Lambda(1520) production as an empirical measure of rescattering in the deuteron, the cross section upper limit for the elementary gamman --> K-Theta+ reaction is estimated to be a factor of 10 higher, i.e., approximately 3 nb (95% C.L.).

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@article{McKinnon2006SearchFT, title={Search for the Theta+ pentaquark in the reaction gammad --> pK-K+n.}, author={B . McKinnon and Kenneth Hicks and N . A . Baltzell and Daniel S. Carman and M . D . Mestayer and T . Mibe and M . Mirazita and Silvia Niccolai and Piero Rossi and S . S . Stepanyan and D . J . Tedeschi and P . Ambrozewicz and Marco Anghinolfi and G . Asryan and Harut Avakian and H . Bagdasaryan and Nathan Baillie and John P. Ball and V . Batourine and Marco Battaglieri and I . Bedlinskiy and Matthew Bellis and N . Benmouna and Barry L. Berman and A . S . Biselli and Sylvain Bouchigny and S . Boiarinov and Robert Bradford and Derek Branford and William J. Briscoe and W . K . Brooks and Stephen Bueltmann and Volker D. Burkert and Cornel Butuceanu and John R. Calarco and S . L . Careccia and S Chen and Philip L. Cole and Patrick B Collins and P . Coltharp and Don Crabb and V . Cred{\'e} and Douglas Dale and R De Masi and R Devita and Elena De Sanctis and P . V . Degtyarenko and A . Deur and C . Djalali and Gail E. Dodge and Jeff Donnelly and Dan Doughty and M . Dugger and Oleksandr P. Dzyubak and H . Egiyan and K . Sh . Egiyan and Latifa Elouadrhiri and Pomarici Eugenio and G . V . Fedotov and Gary J. Feldman and Herbert O. Funsten and M . Y . Gabrielyan and Lu Gan and Michel Garçon and Alexander Gasparian and G . V . Gavalian and Gerard P. Gilfoyle and Kevin Giovanetti and F-X. Girod and James T Goetz and A . Gonenc and R . W . Gothe and Keith A Griffioen and Michel Guidal and Nevzat Guler and L. Guo and V. Gyurjyan and Rafael S Hakobyan and F William Hersman and I . Hleiqawi and M. Holtrop and Charles Earl Hyde-Wright and Y . Y . Ilieva and D. G. Ireland and B. S. Ishkhanov and Masaaki Ito and D . J . A . Jenkins and H . Siswoyo Jo and Kyungseon Joo and H . G . Juengst and J . D . Kellie and Mustakimur Khandaker and Won Ho Kim and A . E . Klein and F . J . Klein and Mikhail Kossov and Laird H. Kramer and V . P . Kubarovsky and Jens Kuhn and Sebastian E. Kuhn and Sergey V. Kuleshov and J . Lachniet and Jessica Langheinrich and Dr . A . Arul Lawrence and Kathryn Livingston and He Jun Lu and M Maccormick and Bernd Mecking and Cristopher A . Meyer and K . Yu . Mikhailov and R . A . Miskimen and V . I . Mokeev and Samantha Morrow and Maryam Moteabbed and G . S . Mutchler and Ichiro Nakagawa and P. Nadel-Turoński and R . Nasseripour and Gabriel Niculescu and Ionut-Mihai Niculescu and Boguslaw B. Niczyporuk and Megh Raj Niroula and R . A . Niyazov and Mina Nozar and Michail Osipenko and A . I . Ostrovidov and K H Park and E . Pasyuk and Christopher Paterson and J . W . Pierce and N A Pivnyuk and O . Pogorelko and S . Pozdniakov and J William Price and Yelena Prok and D . Protopopescu and Brian A. Raue and Gianni Ricco and Marco Ripani and B . G . Ritchie and Franco Ronchetti and G . Rosner and Franck Sabati{\'e} and Cec{\'i}lia Salgado and Joseph P Santoro and V. Sapunenko and R. Alexander Schumacher and Vassili Serov and Yu. Sharabian and Ernest S. Smith and L . Courtney Smith and Daniel I. Sober and A . Stavinsky and Brandon Stokes and Paul Stoler and Igor Strakovsky and Sonja Strauch and M . Taiuti and A. Teymurazyan and Ulrich Thoma and Avtandil Tkabladze and S . Tkachenko and Clarisse Tur and M . Ungaro and Michael Vineyard and A . V . Vlassov and L . B . Weinstein and Dennis P. Weygand and M . R . J . Williams and Edward M . Wolin and Madeleine Wood and A . Yegneswaran and Lorenzo Zana and Jason Y. Zhang and B Zhao and Z. Zhao}, journal={Physical review letters}, year={2006}, volume={96 21}, pages={212001} }