Publications

2007

1. Measurement of density correlations in pseudorapidity via charged particle multiplicity fluctuations in Au+Au collisions at sNN=200 GeV

   Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Alexander J., Amirikas R., Aphecetche L., Aronson S. H., Averbeck R., Awes T. C., Azmoun R., Babintsev V., Baldisseri A., Barish K. N., Barnes P. D., Bassalleck B., Bathe S., Batsouli S., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical Review C. 76, 3, 034903.  Abstract

   Longitudinal density correlations of produced matter in Au+Au collisions at sNN=200 GeV have been measured from the inclusive charged particle distributions as a function of pseudorapidity window sizes. The extracted αξ parameter, related to the susceptibility of the density fluctuations in the long-wavelength limit, exhibits a nonmonotonic behavior as a function of the number of participant nucleons, Npart. A local maximum is seen at Npart~90, with corresponding energy density based on the Bjorken picture of εBjτ~2.4 GeV/(fm2c) with a transverse area size of 60 fm2. This behavior may suggest a critical phase boundary based on the Ginzburg-Landau framework.

   [All authors]
2. Detailed study of high-pT neutral pion suppression and azimuthal anisotropy in Au+Au collisions at sNN=200 GeV

   Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Alexander J., Amirikas R., Aphecetche L., Aronson S. H., Averbeck R., Awes T. C., Azmoun R., Babinstev V., Baldisseri A., Barish K. N., Barnes P. D., Bassalleck B., Bathe S., Batsouli S., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical Review C. 76, 3, 034904.  Abstract

   Measurements of neutral pion (π0) production at midrapidity in sNN=200 GeV Au+Au collisions as a function of transverse momentum, pT, collision centrality, and angle with respect to reaction plane are presented. The data represent the final π0 results from the PHENIX experiment for the first RHIC Au+Au run at design center-of-mass energy. They include additional data obtained using the PHENIX Level-2 trigger with more than a factor of 3 increase in statistics over previously published results for pT>6 GeV/c. We evaluate the suppression in the yield of high-pT π0's relative to pointlike scaling expectations using the nuclear modification factor RAA. We present the pT dependence of RAA for nine bins in collision centrality. We separately integrate RAA over larger pT bins to show more precisely the centrality dependence of the high-pT suppression. We then evaluate the dependence of the high-pT suppression on the emission angle Δ of the pions with respect to event reaction plane for seven bins in collision centrality. We show that the yields of high-pT π0's vary strongly with Δ, consistent with prior measurements. We show that this variation persists in the most peripheral bin accessible in this analysis. For the peripheral bins we observe no suppression for neutral pions produced aligned with the reaction plane, whereas the yield of π0's produced perpendicular to the reaction plane is suppressed by a factor of ~2. We analyze the combined centrality and Δ dependence of the π0 suppression in different pT bins using different possible descriptions of parton energy loss dependence on jet path-length averages to determine whether a single geometric picture can explain the observed suppression pattern.

   [All authors]
3. Inclusive cross section and double helicity asymmetry for π0 production in p+p collisions at s=200GeV: Implications for the polarized gluon distribution in the proton

   Adare A., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Bataineh H., Alexander J., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Baksay G., Baksay L., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical Review D. 76, 5, 051106.  Abstract

   The PHENIX experiment presents results from the Relativistic Heavy Ion Collider 2005 run with polarized proton collisions at s=200GeV, for inclusive π0 production at midrapidity. Unpolarized cross section results are given for transverse momenta pT=0.5 to 20GeV/c, extending the range of published data to both lower and higher pT. The cross section is described well for pT2GeV/c, by perturbative QCD. Double helicity asymmetries ALL are presented based on a factor of 5 improvement in uncertainties as compared to previously published results, due to both an improved beam polarization of 50%, and to higher integrated luminosity. These measurements are sensitive to the gluon polarization in the proton. Using one representative model of gluon polarization it is demonstrated that the gluon spin contribution to the proton spin is significantly constrained.

   [All authors]
4. J/ψ production versus centrality, transverse momentum, and rapidity in Au+Au collisions at s NN=200 GeV

   Adare A., Afanasiev S., Aidala C., Ajitanand N., Akiba Y., Al-Bataineh H., Alexander J., Al-Jamel A., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Baksay G., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical review letters. 98, 23, 232301.  Abstract

   The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/ψ production for rapidities -2.2

   [All authors]
5. J/ψ Production vs Transverse Momentum and Rapidity in p+p Collisions at √s = 200 GeV

   Adare A., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Bataineh H., Alexander J., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Baksay G., Baksay L., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical review letters. 98, 23, 232002.  Abstract

   J/ψ production in p+p collisions at √s = 200 GeV has been measured in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) over a rapidity range of -2.2 u · σ^J/ψ_pp = 178±3^stat±53^sys±18^norm nb.

   [All authors]
6. Correlated production of p and over(p, ̄) in Au + Au collisions at sqrt(s_{N N}) = 200   GeV

   Adare A., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Bataineh H., Alexander J., Al-Jamel A., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Baksay G., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physics Letters B. 649, 5-6, p. 359-369  Abstract

   Correlations between p and over(p, ̄) at transverse momenta typical of enhanced baryon production in Au + Au collisions are reported. The PHENIX experiment has measured same and opposite sign baryon pairs in Au + Au collisions at sqrt(s_{N N}) = 200   GeV. Correlated production of p and over(p, ̄) with the trigger particle from the range 2.5 T T T range rises with increasing centrality, except for the most central collisions, where baryons show a significantly smaller number of associated mesons. These data are consistent with a picture in which hard scattered partons produce correlated p and over(p, ̄) in the p_T region of the baryon excess.

   [All authors]
7. Erratum: J/ψ production versus centrality, transverse momentum, and rapidity in Au+Au collisions at sNN=200GeV (Physics Review Letters (2007) 98 (232301))

   Adare A., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Bataineh H., Alexander J., Al-Jamel A., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Baksay G., Baksay L., Baldisseri A., Barish K. N., Barnes P. D., Bassalleck B., Bathe S., Batsouli S., Baublis V., Bauer F., Bazilevsky A., Belikov S., Bennett R., Berdnikov Y., Bickley A. A., Bjorndal M. T., Boissevain J. G., Borel H., Boyle K., Brooks M. L., Brown D. S., Bucher D., Buesching H., Bumazhnov V., Bunce G., Burward-Hoy J. M., Butsyk S., Campbell S., Chai J. S., Chang B. S., Charvet J. L., Chernichenko S., Chiba J., Chi C. Y., Chiu M., Choi I. J., Chujo T., Chung P., Churyn A., Cianciolo V., Cleven C. R., Cobigo Y., Cole B. A., Comets M. P., Constantin P., Csanad M., Csorgo T., Dahms T., Das K., David G., Deaton M. B., Dehmelt K., Delagrange H., Denisov A., D'Enterria D., Deshpande A., Desmond E. J., Dietzsch O., Dion A., Donadelli M., Drachenberg J. L., Drapier O., Drees A., Dubey A. K., Durum A., Dzhordzhadze V., Efremenko Y. V., Egdemir J., Ellinghaus F., Emam W. S., Enokizono A., En'Yo H., Espagnon B., Esumi S., Eyser K. O., Fields D. E., Finger M., Fleuret F., Fokin S. L., Forestier B., Fraenkel Z., Frantz J. E., Franz A., Franz J., Frawley A. D., Fujiwara K., Fukao Y., Fung S. Y., Fusayasu T., Gadrat S., Garishvili I., Gastineau F., Germain M., Glenn A., Gong H., Gonin M., Gosset J., Goto Y., Granier De Cassagnac R., Grau N., Greene S. V., Grosse Perdekamp M., Gunji T., Gustafsson H. A., Hachiya T., Hadj Henni A., Haegemann C., Haggerty J. S., Hagiwara M. N., Hamagaki H., Han R., Harada H., Hartouni E. P., Haruna K., Harvey M., Haslum E., Hasuko K., Hayano R., Heffner M., Hemmick T. K., Hester T., Heuser J. M., He X., Hiejima H., Hill J. C., Hobbs R., Hohlmann M., Holmes M., Holzmann W., Homma K., Hong B., Horaguchi T., Hornback D., Hur M. G., Ichihara T., Imai K., Inaba M., Inoue Y., Isenhower D., Isenhower L., Ishihara M., Isobe T., Issah M., Isupov A., Jacak B. V., Jia J., Jin J., Jinnouchi O., Johnson B. M., Joo K. S., Jouan D., Kajihara F., Kametani S., Kamihara N., Kamin J., Kaneta M., Kang J. H., Kanou H., Kawagishi T., Kawall D., Kazantsev A. V., Kelly S., Khanzadeev A., Kikuchi J., Kim D. H., Kim D. J., Kim E., Kim Y. S., Kinney E., Kiss A., Kistenev E., Kiyomichi A., Klay J., Klein-Boesing C., Kochenda L., Kochetkov V., Komkov B., Konno M., Kotchetkov D., Kozlov A., Kral A., Kravitz A., Kroon P. J., Kubart J., Kunde G. J., Kurihara N., Kurita K., Kweon M. J., Kwon Y., Kyle G. S., Lacey R., Lai Y. S., Lajoie J. G., Lebedev A., Le Bornec Y., Leckey S., Lee D. M., Lee M. K., Lee T., Leitch M. J., Leite M. A., Lenzi B., Lim H., Liska T., Litvinenko A., Liu M. X., Li X., Li X. H., Love B., Lynch D., Maguire C. F., Makdisi Y. I., Malakhov A., Malik M. D., Manko V. I., Mao Y., Masek L., Masui H., Matathias F., McCain M. C., McCumber M., McGaughey P. L., Miake Y., Mikes P., Miki K., Miller T. E., Milov A., Mioduszewski S., Mishra G. C., Mishra M., Mitchell J. T., Mitrovski M., Morreale A., Morrison D. P., Moss J. M., Moukhanova T. V., Mukhopadhyay D., Murata J., Nagamiya S., Nagata Y., Nagle J. L., Naglis M., Nakagawa I., Nakamiya Y., Nakamura T., Nakano K., Newby J., Nguyen M., Norman B. E., Nyanin A. S., Nystrand J., O'Brien E., Oda S. X., Ogilvie C. A., Ohnishi H., Ojha I. D., Okada H., Okada K., Oka M., Omiwade O. O., Oskarsson A., Otterlund I., Ouchida M., Ozawa K., Pak R., Pal D., Palounek A. P., Pantuev V., Papavassiliou V., Park J., Park W. J., Pate S. F., Pei H., Peng J. C., Pereira H., Peresedov V., Peressounko D. Y., Pinkenburg C., Pisani R. P., Purschke M. L., Purwar A. K., Qu H., Rak J., Rakotozafindrabe A., Ravinovich I., Read K. F., Rembeczki S., Reuter M., Reygers K., Riabov V., Riabov Y., Roche G., Romana A., Rosati M., Rosendahl S. S., Rosnet P., Rukovatkin P., Rykov V. L., Ryu S. S., Sahlmueller B., Saito N., Sakaguchi T., Sakai S., Sakata H., Samsonov V., Sato H. D., Sato S., Sawada S., Seele J., Seidl R., Semenov V., Seto R., Sharma D., Shea T. K., Shein I., Shevel A., Shibata T. A., Shigaki K., Shimomura M., Shohjoh T., Shoji K., Sickles A., Silva C. L., Silvermyr D., Silvestre C., Sim K. S., Singh C. P., Singh V., Skutnik S., Slunecka M., Smith W. C., Soldatov A., Soltz R. A., Sondheim W. E., Sorensen S. P., Sourikova I. V., Staley F., Stankus P. W., Stenlund E., Stepanov M., Ster A., Stoll S. P., Sugitate T., Suire C., Sullivan J. P., Sziklai J., Tabaru T., Takagi S., Takagui E. M., Taketani A., Tanaka K. H., Tanaka Y., Tanida K., Tannenbaum M. J., Taranenko A., Tarjan P., Thomas T. L., Togawa M., Toia A., Tojo J., Tomasek L., Torii H., Towell R. S., Tram V. N., Tserruya I., Tsuchimoto Y., Tuli S. K., Tydesjo H., Tyurin N., Vale C., Valle H., Van Hecke H. W., Velkovska J., Vertesi R., Vinogradov A. A., Virius M., Vrba V., Vznuzdaev E., Wagner M., Walker D., Wang X. R., Watanabe Y., Wessels J., White S. N., Willis N., Winter D., Woody C. L., Wysocki M., Xie W., Yamaguchi Y., Yanovich A., Yasin Z., Ying J., Yokkaichi S., Young G. R., Younus I., Yushmanov I. E., Zajc W. A., Zaudtke O., Zhang C., Zhou S., Zimanyi J., Zolin L. et al. (2007) Physical review letters. 98, 24, 249902.  Abstract

   [All authors]
8. System size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at sNN=200 and 62.4 GeV

   Adare A., Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Bataineh H., Alexander J., Al-Jamel A., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical review letters. 98, 23, 232302.  Abstract

   We present azimuthal angle correlations of intermediate transverse momentum (1-4GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Δ =π in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.

   [All authors]
9. Production of ω mesons at large transverse momenta in p+p and d+Au collisions at sNN=200 GeV

   Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Jamel A., Alexander J., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Averbeck R., Awes T. C., Babintsev V., Baldisseri A., Barish K. N., Barnes P. D., Bassalleck B., Bathe S., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical Review C. 75, 5, 051902.  Abstract

   The PHENIX experiment at RHIC has measured the invariant cross section for ω-meson production at midrapidity in the transverse momentum range 2.5

   [All authors]
10. Energy loss and flow of heavy quarks in Au+Au collisions at sNN=200GeV

    Adare A., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Bataineh H., Alexander J., Al-Jamel A., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Asai J., Atomssa E. T., Averbeck R., Awes T. C., Azmoun B., Babintsev V., Baksay G., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical review letters. 98, 17, 172301.  Abstract

    The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3

    [All authors]
11. Centrality dependence of π0 and η production at large transverse momentum in sNN=200GeV d+Au collisions

    Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Al-Jamel A., Alexander J., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Averbeck R., Awes T. C., Babintsev V., Baldisseri A., Barish K. N., Barnes P. D., Bassalleck B., Bathe S., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical review letters. 98, 17, 172302.  Abstract

    The dependence of transverse momentum spectra of neutral pions and η mesons with pT

    [All authors]
12. Evidence for a long-range component in the pion emission source in Au+Au collisions at sNN=200GeV

    Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Alexander J., Amirikas R., Aphecetche L., Aronson S. H., Averbeck R., Awes T. C., Azmoun R., Babintsev V., Baldisseri A., Barish K. N., Barnes P. D., Bassalleck B., Bathe S., Batsouli S., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical review letters. 98, 13, 132301.  Abstract

    Emission source functions are extracted from correlation functions constructed from charged pions produced at midrapidity in Au+Au collisions at sNN=200GeV. The source parameters extracted from these functions at low kT give first indications of a long tail for the pion emission source. The source extension cannot be explained solely by simple kinematic considerations. The possible role of a halo of secondary pions from resonance emissions is explored.

    [All authors]
13. Low-mass dielectrons from the PHENIX experiment at RHIC

    Kozlov A., Dubey A. K., Makek M., Milov A., Sharma D. & Tserruya I. (2007) European Physical Journal A. 31, 4, p. 836-841  Abstract

    The production of the low-mass dielectrons is considered to be a powerful tool to study the properties of the hot and dense matter created in the ultra-relativistic heavy-ion collisions. We present the preliminary results on the first measurements of the low-mass dielectron continuum in Au + Au collisions and the φ-meson production measured in Au + Au and d + Au collisions at √8_NN= 200GeV performed by the PHENIX experiment.

14. High transverse momentum η meson production in p+p,d+Au, and Au+Au collisions at sNN=200 GeV

    Adler S. S., Afanasiev S., Aidala C., Ajitanand N. N., Akiba Y., Alexander J., Al-Jamel A., Amirikas R., Aoki K., Aphecetche L., Armendariz R., Aronson S. H., Averbeck R., Awes T. C., Azmoun R., Babintsev V., Baldisseri A., Barish K. N., Barnes P. D., Dubey A. K., Makek M., Milov A., Sharma D., Tserruya I. et al. (2007) Physical Review C. 75, 2, 024909.  Abstract

    Inclusive transverse momentum spectra of η mesons in the range pTf2-12 GeV/c have been measured at midrapidity (|η|

    [All authors]
15. Understanding the gain characteristics of GEMs inside the Hadron Blind Detector in PHENIX

    Anderson W., Azmoun B., Chi C. Y., Citron Z., Dubey A., Durham J. M., Fraenkel Z., Hemmick T., Kamin J., Kozlov A., Milov A., Naglis M., Pisani R., Ravinovich I., Sakaguehi T., Sharma D., Sickles A., Tserruya I., Woody C. et al. (2007) 2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC. p. 4662-4665  Abstract

    The Hadron Blind Detector (HBD) is new upgrade detector for the PHENIX experiment at RHIC that consists of a windowless Cherenkov radiator directly coupled to a set of triple Gas Electron Multipliers (GEMs). The individual GEMs measure 22×27 cm², and the top GEM in the stack is coated with a ∼300 nm layer of CsI that serves as a photocathode. The signal amplitude from the triple GEM stack is used to differentiate between single isolated electrons and overlapping electrons from close pairs. Therefore, the absolute gain of the GEM stack is a crucial parameter in understanding and interpreting the data. We accumulated extensive data on the GEMs during the design and construction of the detector, including gain variation with time, charging effects, saturation, gain uniformity, and source rate dependence. These results, as well as our experience in operating the detector during its first run at RHIC, will be presented at the Workshop.

    [All authors]
16. A faster digitizer system for the hadron blind detector in PHENIX

    Chi C. Y., Anderson W., Azmoun B., Citron Z., Dubey A., Durham M., Fraenkel Z., Harder J., Hemmick T., Kamin J., Kozlov A., Milov A., Naglis M., O'Connor P., Pisani R. P., Radeka V., Ravinovich I., Sakaguchi T., Sharma D., Sickles A., Sippach F. W., Stoll S., Tserruya I., Woody C., Yu B. et al. (2007) 2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC. p. 1997-2000  Abstract

    A Hadron Blind Detector (HBD) has been installed in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). A 2300 channel compact 12-bit 60 MHz digitizer system has been built to read the HBD system. The raw signals are shaped with 70 ns rise time and are directly digitized. The time and charge of the raw signals can be calculated from the multiple samples. The system is designed to handle Level 1 (L1) trigger rates up to 25 KHz with 5 L1 event buffers. Large amounts of data are generated after the ADC. Issues regarding clock distribution, data handling, event buffers, and L1 trigger primitive generations have been addressed. The overall system performance will also be discussed.

    [All authors]