-
collaboration,
E. Aprile,
M. Alfonsi,
K. Arisaka,
F. Arneodo,
C. Balan,
L. Baudis,
B. Bauermeister,
A. Behrens,
P. Beltrame, [......],
P. R. Scovell,
M. Selvi,
P. Shagin,
H. Simgen,
A. Teymourian,
D. Thers,
O. Vitells,
H. Wang,
M. Weber,
C. Weinheimer
[show abstract]
[hide abstract]
ABSTRACT: We present new experimental constraints on the elastic, spin-dependent
WIMP-nucleon cross section using recent data from the XENON100 experiment,
operated in the Laboratori Nazionali del Gran Sasso in Italy. An analysis of
224.6 live days x 34 kg of exposure acquired during 2011 and 2012 revealed no
excess signal due to axial-vector WIMP interactions with 129-Xe and 131-Xe
nuclei. This leads to the most stringent upper limits on WIMP-neutron cross
sections for WIMP masses above 6 GeV, with a minimum cross section of 3.5 x
10^{-40} cm^2 at a WIMP mass of 45 GeV, at 90% confidence level.
01/2013;
-
E. Aprile,
M. Alfonsi,
K. Arisaka,
F. Arneodo,
C. Balan,
L. Baudis,
A. Behrens,
P. Beltrame,
K. Bokeloh,
E. Brown, [......],
P. R. Scovell,
M. Selvi,
P. Shagin,
H. Simgen,
A. Teymourian,
D. Thers,
O. Vitells,
H. Wang,
M. Weber,
C. Weinheimer
[show abstract]
[hide abstract]
ABSTRACT: The XENON100 experiment, in operation at the Laboratori Nazionali del Gran
Sasso (LNGS) in Italy, was designed to search for evidence of dark matter
interactions inside a volume of liquid xenon using a dual-phase time projection
chamber. This paper describes the Slow Control System (SCS) of the experiment
with emphasis on the distributed architecture as well as on its modular and
expandable nature. The system software was designed according to the rules of
Object-Oriented Programming and coded in Java, thus promoting code reusability
and maximum flexibility during commissioning of the experiment. The SCS has
been continuously monitoring the XENON100 detector since mid 2008, remotely
recording hundreds of parameters on a few dozen instruments in real time, and
setting emergency alarms for the most important variables.
11/2012;
-
E Aprile,
M Alfonsi,
K Arisaka,
F Arneodo,
C Balan,
L Baudis,
B Bauermeister,
A Behrens,
P Beltrame,
K Bokeloh, [......],
P R Scovell,
M Selvi,
P Shagin,
H Simgen,
A Teymourian,
D Thers,
O Vitells,
H Wang,
M Weber,
C Weinheimer
[show abstract]
[hide abstract]
ABSTRACT: We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso for 13 months during 2011 and 2012. XENON100 features an ultralow electromagnetic background of (5.3±0.6)×10^{-3} events/(keV_{ee}×kg×day) in the energy region of interest. A blind analysis of 224.6 live days×34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the predefined nuclear recoil energy range of 6.6-30.5 keV_{nr} are consistent with the background expectation of (1.0±0.2) events. A profile likelihood analysis using a 6.6-43.3 keV_{nr} energy range sets the most stringent limit on the spin-independent elastic weakly interacting massive particle-nucleon scattering cross section for weakly interacting massive particle masses above 8 GeV/c^{2}, with a minimum of 2×10^{-45} cm^{2} at 55 GeV/c^{2} and 90% confidence level.
Physical Review Letters 11/2012; 109(18):181301. · 7.37 Impact Factor
-
The XENON Collaboration,
E. Aprile,
M. Alfonsi,
K. Arisaka,
F. Arneodo,
C. Balan,
L. Baudis,
B. Bauermeister,
A. Behrens,
P. Beltrame, [......],
P. R. Scovell,
M. Selvi,
P. Shagin,
H. Simgen,
A. Teymourian,
D. Thers,
O. Vitells,
H. Wang,
M. Weber,
C. Weinheimer
[show abstract]
[hide abstract]
ABSTRACT: In a recent manuscript (arXiv:1208.5046) Peter Sorensen claims that
XENON100's upper limits on spin-independent WIMP-nucleon cross sections for
WIMP masses below 10 GeV "may be understated by one order of magnitude or
more". Having performed a similar, though more detailed analysis prior to the
submission of our new result (arXiv:1207.5988), we do not confirm these
findings. We point out the rationale for not considering the described effect
in our final analysis and list several potential problems with his study.
08/2012;
-
A. Adare,
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
H. Al-Bataineh,
A. Al-Jamel,
J. Alexander,
A. Angerami, [......],
G. R. Young,
I. Younus,
I. E. Yushmanov,
W. A. Zajc,
O. Zaudtke,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
[show abstract]
[hide abstract]
ABSTRACT: Direct photons have been measured in sqrt(s_NN)=200 GeV d+Au collisions at
midrapidity. A wide p_T range is covered by measurements of nearly-real virtual
photons (1<p_T<6 GeV/c) and real photons (5<p_T<16 GeV/c). The invariant yield
of the direct photons in d+Au collisions over the scaled p+p cross section is
consistent with unity. Theoretical calculations assuming standard cold nuclear
matter effects describe the data well for the entire p_T range. This indicates
that the large enhancement of direct photons observed in Au+Au collisions for
1.0<p_T<2.5 GeV/c is due to a source other than the initial-state nuclear
effects.
08/2012;
-
The Collaboration,
E. Aprile,
M. Alfonsi,
K. Arisaka,
F. Arneodo,
C. Balan,
L. Baudis,
A. Behrens,
P. Beltrame,
K. Bokeloh, [......],
P. R. Scovell,
M. Selvi,
P. Shagin,
H. Simgen,
A. Teymourian,
D. Thers,
O. Vitells,
H. Wang,
M. Weber,
C. Weinheimer
[show abstract]
[hide abstract]
ABSTRACT: The XENON100 experiment, situated in the Laboratori Nazionali del Gran Sasso,
aims at the direct detection of dark matter in the form of weakly interacting
massive particles (WIMPs), based on their interactions with xenon nuclei in an
ultra low background dual-phase time projection chamber. This paper describes
the general methods developed for the analysis of the XENON100 data, focusing
on the 100.9 live days science run from which results on spin-independent
elastic and inelastic WIMP-nucleon cross-sections have already been reported.
07/2012;
-
Wan-Ting Chen,
D. Chbib, J. -P. Cussonneau,
J. Donnard,
S. Duval,
O. Lemaire,
M. Le Calloch,
P. Le Ray,
A. -F. Mohamad-Hadi,
E. Morteau,
T. Oger,
L. Scotto-Lavina,
J. -S. Stutzmann,
D. Thers,
P. Briend,
T. Haruyama,
S. Mihara,
T. Tauchi
[show abstract]
[hide abstract]
ABSTRACT: We have developed a compact cryogenic system with a pulse tube refrigerator
and a coaxial heat exchanger. This liquefaction-purification system not only
saves the cooling power used to reach high gaseous recirculation rate, but also
reduces the impurity level with high speed. The heat exchanger operates with an
efficiency of 99%, which indicates the possibility for fast xenon gas
recirculation in a highpressurized large-scale xenon storage with much less
thermal losses.
05/2012;
-
T. Oger,
W T Chen, J P Cussonneau,
J. Donnard,
S. Duval,
J. Lamblin,
O. Lemaire,
A. -F. Mohamad-Hadi,
P. Le Ray,
E. Morteau,
L. Scotto Lavina,
J. -S. Stutzmann,
D. Thers
[show abstract]
[hide abstract]
ABSTRACT: A new technique for medical imaging, "3{\gamma} imaging", is studied by our
group at SUBATECH for few years. A small liquid xenon time projection chamber
prototype has been built in order to demonstrate the feasibility of this
technique. With an ultra-low-noise front-end electronics, the energy deposit
and resolution of 511 keV {\gamma}-ray as a function of drift electric field
(E) is measured with high precision. 500 {\mu}m of z resolution is estimated by
measuring the charge carriers drift velocity and time resolution.
09/2011;
-
W T Chen,
H. Carduner, J P Cussonneau,
J. Donnard,
S. Duval,
A. -F. Mohamad-Hadi,
J. Lamblin,
O. Lemaire,
P. Le Ray,
E. Morteau,
T. Oger,
L. Scotto Lavina,
J. -S. Stutzmann,
D. Thers
[show abstract]
[hide abstract]
ABSTRACT: Liquid xenon (LXe) is a very attractive material as a detection medium for
ionization detectors due to its high density, high atomic number, and low
energy required to produce electron-ion pairs. Therefore it has been used in
several applications, like {\gamma} detection or direct detection of dark
matter. Now Subatech is working on the R & D of LXe Compton telescope for
3{\gamma} medical imaging, which can make precise tridimensional localization
of a ({\beta}+, {\gamma}) radioisotope emitter. The diffusion of charge
carriers will directly affect the spatial resolution of LXe ionization signal.
We will report how we measure the transverse diffusion coefficient for
different electric field (0.5 ~ 1.2 kV/cm) by observing the spray of charge
carriers on drift length varying until 12cm. With very-low-noise front-end
electronics and complete Monte-Carlo simulation of the experiment, the values
of transverse diffusion coefficient are measured precisely.
09/2011;
-
S. Duval,
A. Breskin,
R. Budnik,
W T Chen,
H. Carduner,
M. Cortesi, J P Cussonneau,
J. Donnard,
J. Lamblin,
P. Le Ray,
E. Morteau,
T. Oger,
J. -S. Stutzmann,
D. Thers
[show abstract]
[hide abstract]
ABSTRACT: Operation results are presented of a UV-sensitive gaseous photomultiplier
(GPM) coupled through a MgF2 window to a liquid-xenon scintillator. It
consisted of a reflective CsI photocathode deposited on top of a THick Gaseous
Electron Multiplier (THGEM); further multiplication stages were either a second
THGEM or a Parallel Ionization Multiplier (PIM) followed by a MICROMEsh GAseous
Structure (MICROMEGAS). The GPM operated in gas-flow mode with non-condensable
gas mixtures. Gains of 10^4 were measured with a CsI-coated double-THGEM
detector in Ne/CH4 (95:5), Ne/CF4 (95:5) and Ne/CH4/CF4 (90:5:5), with soft
X-rays at 173 K. Scintillation signals induced by alpha particles in liquid
xenon were measured here for the first time with a double-THGEM GPM in He/CH4
(92.5:7.5) and a triple-structure THGEM/PIM/MICROMEGAS GPM in Ne/CH4 (90:10)
with a fast-current preamplifier.
01/2011;
-
A. Adare,
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
H. Al-Bataineh,
J. Alexander,
A. Al-Jamel,
K. Aoki, [......],
G. R. Young,
I. Younus,
I. E. Yushmanov,
W. A. Zajc,
O. Zaudtke,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
[show abstract]
[hide abstract]
ABSTRACT: A comprehensive survey of event-by-event fluctuations of charged hadron multiplicity in relativistic heavy ions is presented. The survey covers Au+Au collisions at √sNN=62.4 and 200 GeV, and Cu+Cu collisions at √sNN=22.5,62.4, and 200 GeV. Fluctuations are measured as a function of collision centrality, transverse momentum range, and charge sign. After correcting for nondynamical fluctuations due to fluctuations in the collision geometry within a centrality bin, the remaining dynamical fluctuations expressed as the variance normalized by the mean tend to decrease with increasing centrality. The dynamical fluctuations are consistent with or below the expectation from a superposition of participant nucleon-nucleon collisions based upon p+p data, indicating that this dataset does not exhibit evidence of critical behavior in terms of the compressibility of the system. A comparison of the data with a model where hadrons are independently emitted from a number of hadron clusters suggests that the mean number of hadrons per cluster is small in heavy ion collisions.
Phys. Rev. C. 10/2008; 78(4).
-
A. Adare,
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
H. Al-Bataineh,
J. Alexander,
A. Al-Jamel,
K. Aoki, [......],
G. R. Young,
I. Younus,
I. E. Yushmanov,
W. A. Zajc,
O. Zaudtke,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
[show abstract]
[hide abstract]
ABSTRACT: We present a new analysis of J/ψ production yields in deuteron-gold collisions at √sNN=200 GeV using data taken from the PHENIX experiment in 2003 and previously published in S. S. Adler et al. [Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/ψ data taken in 2005 are used to improve the baseline measurement and thus construct updated cold nuclear matter modification factors (RdAu). A suppression of J/ψ in cold nuclear matter is observed as one goes forward in rapidity (in the deuteron-going direction), corresponding to a region more sensitive to initial-state low-x gluons in the gold nucleus. The measured nuclear modification factors are compared to theoretical calculations of nuclear shadowing to which a J/ψ (or precursor) breakup cross section is added. Breakup cross sections of σbreakup=2.8-1.4+1.7 (2.2-1.5+1.6) mb are obtained by fitting these calculations to the data using two different models of nuclear shadowing. These breakup cross-section values are consistent within large uncertainties with the 4.2±0.5 mb determined at lower collision energies. Projecting this range of cold nuclear matter effects to copper-copper and gold-gold collisions reveals that the current constraints are not sufficient to firmly quantify the additional hot nuclear matter effect.
Phys. Rev. C. 02/2008; 77(2).
-
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
A. Al-Jamel,
J. Alexander,
K. Aoki,
L. Aphecetche,
R. Armendariz, [......],
S. Yokkaichi,
G. R. Young,
I. E. Yushmanov,
W. A. Zajc,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong,
H. W. vanHecke
[show abstract]
[hide abstract]
ABSTRACT: We present transverse momentum (pT) spectra of charged hadrons measured in deuteron-gold and nucleon-gold collisions at √sNN=200 GeV for four centrality classes. Nucleon-gold collisions were selected by tagging events in which a spectator nucleon was observed in one of two forward rapidity detectors. The spectra and yields were investigated as a function of the number of binary nucleon-nucleon collisions, ν, suffered by deuteron nucleons. A comparison of charged particle yields to those in p+p collisions show that yield per nucleon-nucleon collision saturates with ν for high momentum particles. We also present the charged hadron to neutral pion ratios as a function of pT.
Phys. Rev. C. 01/2008; 77(1).
-
A Adare,
S S Adler,
S Afanasiev,
C Aidala,
N N Ajitanand,
Y Akiba,
H Al-Bataineh,
J Alexander,
A Al-Jamel,
K Aoki, [......],
G R Young,
I Younus,
I E Yushmanov,
W A Zajc,
O Zaudtke,
C Zhang,
S Zhou,
J Zimányi,
L Zolin,
X Zong
[show abstract]
[hide abstract]
ABSTRACT: We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi 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.
Physical Review Letters 07/2007; 98(23):232302. · 7.37 Impact Factor
-
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
J. Alexander,
A. Al-Jamel,
R. Amirikas,
K. Aoki,
L. Aphecetche, [......],
S. Yokkaichi,
G. R. Young,
I. E. Yushmanov,
W. A. Zajc,
C. Zhang,
S. Zhou,
S. J. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
[show abstract]
[hide abstract]
ABSTRACT: Inclusive transverse momentum spectra of η mesons in the range pT≈2–12 GeV/c have been measured at midrapidity (|η|<0.35) by the PHENIX experiment at RHIC in p+p,d+Au, and Au+Au collisions at √sNN=200 GeV. The η mesons are reconstructed through their η→γ γ channel for the three colliding systems as well as through the η→π0π+π- decay mode in p+p and d+Au collisions. The nuclear modification factor in d+Au collisions, RdAu(pT)≈1.0–1.1, suggests at most only modest pT broadening (“Cronin enhancement”). In central Au+Au reactions, the η yields are significantly suppressed, with RAuAu(pT)≈0.2. The ratio of η to π0 yields is approximately constant as a function of pT for the three colliding systems in agreement with the high-pT world average of Rη/π0≈0.5 in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range of center-of-mass energies (√sNN≈3–1800 GeV) as well as, for high scaled momentum xp, in e+e- annihilations at √s=91.2 GeV. These results are consistent with a scenario where high-pT η production in nuclear collisions at the Relativistic Heavy Ion Collider is largely unaffected by initial-state effects but where light-quark mesons (π0,η) are equally suppressed due to final-state interactions of the parent partons in the dense medium produced in Au+Au reactions.
Phys. Rev. C. 02/2007; 75(2).
-
S S Adler,
S Afanasiev,
C Aidala,
N N Ajitanand,
Y Akiba,
A Al-Jamel,
J Alexander,
K Aoki,
L Aphecetche,
R Armendariz, [......],
G R Young,
I E Yushmanov,
W A Zajc,
O Zaudtke,
C Zhang,
S Zhou,
J Zimányi,
L Zolin,
X Zong,
H W Van Hecke
[show abstract]
[hide abstract]
ABSTRACT: Cross sections for midrapidity production of direct photons in p+p collisions at the Relativistic Heavy Ion Collider (RHIC) are reported for transverse momenta of 3 < pT < 16 GeV/c. Next-to-leading order perturbative QCD (pQCD) describes the data well for pT >5 GeV/c, where the uncertainties of the measurement and theory are comparable. We also report on the effect of requiring the photons to be isolated from parton jet energy. The observed fraction of isolated photons is well described by pQCD for pT >7 GeV/c.
Physical Review Letters 01/2007; 98(1):012002. · 7.37 Impact Factor
-
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
A. Al-Jamel,
J. Alexander,
K. Aoki,
L. Aphecetche,
R. Armendariz, [......],
A. Yanovich,
S. Yokkaichi,
G. R. Young,
I. E. Yushmanov,
W. A. Zajc,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
[show abstract]
[hide abstract]
ABSTRACT: The properties of jets produced in p+p collisions at √s=200 GeV are measured using the method of two-particle correlations. The trigger particle is a leading particle from a large transverse momentum jet while the associated particle comes from either the same jet or the away-side jet. Analysis of the angular width of the near-side peak in the correlation function determines the jet-fragmentation transverse momentum jT. The extracted value, √⟨jT2⟩=585±6(stat)±15(sys) MeV/c, is constant with respect to the trigger particle transverse momentum, and comparable to the previous lower √s measurements. The width of the away-side peak is shown to be a convolution of jT with the fragmentation variable, z, and the partonic transverse momentum, kT. The ⟨z⟩ is determined through a combined analysis of the measured π0 inclusive and associated spectra using jet-fragmentation functions measured in e+e- collisions. The final extracted values of kT are then determined to also be independent of the trigger particle transverse momentum, over the range measured, with value of √⟨kT2⟩=2.68±0.07(stat)±0.34(sys) GeV/c.
Phys. Rev. D. 10/2006; 74(7).
-
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
A. Al-Jamel,
J. Alexander,
K. Aoki,
L. Aphecetche,
R. Armendariz, [......],
A. Yanovich,
S. Yokkaichi,
G. R. Young,
I. E. Yushmanov,
W. A. Zajc,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
[show abstract]
[hide abstract]
ABSTRACT: PHENIX has measured the centrality dependence of midrapidity pion, kaon, and proton transverse momentum distributions in d+Au and p+p collisions at √sNN=200 GeV. The p+p data provide a reference for nuclear effects in d+Au and previously measured Au+Au collisions. Hadron production is enhanced in d+Au, relative to independent nucleon-nucleon scattering, as was observed in lower energy collisions. The nuclear modification factor for (anti)protons is larger than that for pions. The difference increases with centrality but is not sufficient to account for the abundance of baryon production observed in central Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). The centrality dependence in d+Au shows that the nuclear modification factor increases gradually with the number of collisions encountered by each participant nucleon. We also present comparisons with lower energy data as well as with parton recombination and other theoretical models of nuclear effects on particle production.
Phys. Rev. C. 08/2006; 74(2).
-
A. Adare,
S. S. Adler,
S. Afanasiev,
C. Aidala,
N. N. Ajitanand,
Y. Akiba,
H. Al-Bataineh,
A. Al-Jamel,
J. Alexander,
K. Aoki, [......],
G. R. Young,
I. Younus,
I. E. Yushmanov,
W. A. Zajc,
O. Zaudtke,
C. Zhang,
S. Zhou,
J. Zimányi,
L. Zolin,
X. Zong
Nuclear Physics A 07/2006; 774:949-953. · 1.54 Impact Factor
-
S S Adler,
S Afanasiev,
C Aidala,
N N Ajitanand,
Y Akiba,
A Al-Jamel,
J Alexander,
K Aoki,
L Aphecetche,
R Armendariz, [......],
A Yanovich,
S Yokkaichi,
G R Young,
I E Yushmanov,
W A Zajc,
C Zhang,
S Zhou,
J Zimányi,
L Zolin,
X Zong
[show abstract]
[hide abstract]
ABSTRACT: Deuteron-gold (d+Au) collisions at the Relativistic Heavy Ion Collider provide ideal platforms for testing QCD theories in dense nuclear matter at high energy. In particular, models suggesting strong saturation effects for partons carrying small nucleon momentum fraction (x) predict modifications to jet production at forward rapidity (deuteron-going direction) in d+Au collisions. We report on two-particle azimuthal angle correlations between charged hadrons at forward/backward (deuteron/gold going direction) rapidity and charged hadrons at midrapidity in d+Au and p+p collisions at square root of sNN=200 GeV. Jet structures observed in the correlations are quantified in terms of the conditional yield and angular width of away-side partners. The kinematic region studied here samples partons in the gold nucleus with x~0.1 to ~0.01. Within this range, we find no x dependence of the jet structure in d+Au collisions.
Physical Review Letters 07/2006; 96(22):222301. · 7.37 Impact Factor
