-
COUPP Collaboration,
E. Behnke,
T. Benjamin,
S. J. Brice,
D. Broemmelsiek,
J. I. Collar, P. S. Cooper,
M. Crisler,
C. E. Dahl,
D. Fustin, [......],
W. H. Lippincott,
T. Moan,
T. Nania,
R. Neilson,
E. Ramberg,
A. E. Robinson,
A. Sonnenschein,
E. Vázquez-Jáuregui,
R. A. Rivera,
L. Uplegger
[show abstract]
[hide abstract]
ABSTRACT: We have directly measured the energy threshold and efficiency for bubble
nucleation from iodine recoils in a CF3I bubble chamber in the energy range of
interest for a dark matter search. These interactions cannot be probed by
standard neutron calibration methods, so we develop a new technique by
observing the elastic scattering of 12 GeV/c negative pions. The pions are
tracked with a silicon pixel telescope and the reconstructed scattering angle
provides a measure of the nuclear recoil kinetic energy. The bubble chamber was
operated with a nominal threshold of (13.6+-0.6) keV. Interpretation of the
results depends on the response to fluorine and carbon recoils, but in general
we find agreement with the predictions of the classical bubble nucleation
theory. This measurement confirms the applicability of CF3I as a target for
spin-independent dark matter interactions and represents a novel technique for
calibration of superheated fluid detectors.
04/2013;
-
The SELEX Collaboration,
A. Blanco-Covarrubias,
J. Engelfried,
U. Akgun,
G. Alkhazov,
J. Amaro-Reyes,
A. G. Atamantchouk,
A. S. Ayan,
M. Y. Balatz,
N. F. Bondar, [......],
A. N. Vasiliev,
D. V. Vavilov,
E. Vázquez-Jáuregui,
V. S. Verebryusov,
V. A. Victorov,
V. E. Vishnyakov,
A. A. Vorobyov,
K. Vorwalter,
J. You,
R. Zukanovich-Funchal
[show abstract]
[hide abstract]
ABSTRACT: Using data taken by SELEX during the 1996–1997 fixed target run at Fermilab, we study the production of charmed hadrons on
copper and carbon targets withΣ
−, p, π
−, and π
+ beams. Parametrizing the dependence of the inclusive production cross section on the atomic number A as A
α
, we determine α forD
+, D
0, D
s
+, D
+(2010), Λ
c
+, and their respective anti-particles, as a function of their transverse momentum p
t
and scaled longitudinal momentumx
F
. Within our statistics there is no dependence of α on x
F
for any charm species for the interval 0.1<x
F
<1.0. The average value of α for charm production by pion beams is α
meson=0.850±0.028. This is somewhat larger than the corresponding average α
baryon=0.755±0.016 for charm production by baryon beams (Σ
−, p).
PACS13.85.Ni-14.65.Dw-24.85.+p
European Physical Journal C 04/2012; 64(4):637-644. · 3.63 Impact Factor
-
E. Behnke,
J. Behnke,
S. J. Brice,
D. Broemmelsiek,
J. I. Collar,
A. Conner, P. S. Cooper,
M. Crisler,
C. E. Dahl,
D. Fustin, [......],
M. Hu,
I. Levine,
W. H. Lippincott,
T. Moan,
T. Nania,
E. Ramberg,
A. E. Robinson,
A. Sonnenschein,
M. Szydagis,
E. Vázquez-Jáuregui
[show abstract]
[hide abstract]
ABSTRACT: New data are reported from the operation of a 4.0 kg CF$_{3}$I bubble chamber
in the 6800-foot-deep SNOLAB underground laboratory. The effectiveness of
ultrasound analysis in discriminating alpha-decay background events from single
nuclear recoils has been confirmed, with a lower bound of $>$99.3% rejection of
alpha-decay events. Twenty single nuclear recoil event candidates and three
multiple bubble events were observed during a total exposure of 553 kg-days
distributed over three different bubble nucleation thresholds. The effective
exposure for single bubble recoil-like events was 437.4 kg-days. A neutron
background internal to the apparatus, of known origin, is estimated to account
for five single nuclear recoil events and is consistent with the observed rate
of multiple bubble events. This observation provides world best direct
detection constraints on WIMP-proton spin-dependent scattering for WIMP masses
$>$20 GeV/c$^{2}$ and demonstrates significant sensitivity for spin-independent
interactions.
04/2012;
-
E Behnke,
J Behnke,
S J Brice,
D Broemmelsiek,
J I Collar, P S Cooper,
M Crisler,
C E Dahl,
D Fustin,
J Hall,
J H Hinnefeld,
M Hu,
I Levine,
E Ramberg,
T Shepherd,
A Sonnenschein,
M Szydagis
[show abstract]
[hide abstract]
ABSTRACT: Data from the operation of a bubble chamber filled with 3.5 kg of CF3I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg day, consistent with a neutron background. This observation provides strong direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering for WIMP masses >20 GeV/c2.
Physical Review Letters 01/2011; 106(2):021303. · 7.37 Impact Factor
-
E. Behnke,
J. Behnke,
S. J. Brice,
D. Broemmelsiek,
J. I. Collar, P. S. Cooper,
M. Crisler,
C. E. Dahl,
D. Fustin,
J Hall,
J. H. Hinnefeld,
M. Hu,
I Levine,
E. Ramberg,
T. Shepherd,
A. Sonnenschein,
M. Szydagis
[show abstract]
[hide abstract]
ABSTRACT: Data from the operation of a bubble chamber filled with 3.5 kg of CF$_{3}$I
in a shallow underground site are reported. An analysis of ultrasound signals
accompanying bubble nucleations confirms that alpha decays generate a
significantly louder acoustic emission than single nuclear recoils, leading to
an efficient background discrimination. Three dark matter candidate events were
observed during an effective exposure of 28.1 kg-day, consistent with a neutron
background. This observation provides the strongest direct detection constraint
to date on WIMP-proton spin-dependent scattering for WIMP masses $>20$
GeV/c$^{2}$.
08/2010;
-
A. V. Artamonov,
B. Bassalleck,
B. Bhuyan,
E. W. Blackmore,
D. A. Bryman,
S. Chen,
I.-H. Chiang,
I.-A. Christidi, P. S. Cooper,
M. V. Diwan, [......],
S. Sugimoto,
Y. Tamagawa,
R. Tschirhart,
T. Tsunemi,
D. V. Vavilov,
B. Viren,
Zhe Wang,
N. V. Yershov,
Y. Yoshimura,
T. Yoshioka
[show abstract]
[hide abstract]
ABSTRACT: Experiment E949 at Brookhaven National Laboratory has observed three new events consistent with the decay K+→π+νν̅ in the pion momentum region 140<Pπ<199 MeV/c in an exposure of 1.71×1012 stopped kaons with an estimated total background of 0.93±0.17(stat)-0.24+0.32(syst) events. This brings the total number of observed K+→π+νν̅ events to seven. Combining this observation with previous results, assuming the pion spectrum predicted by the standard model, results in a branching ratio of B(K+→π+νν̅ )=(1.73-1.05+1.15)×10-10. An interpretation of the results for alternative models of the decay K+→π++nothing is also presented.
Phys. Rev. D. 05/2009; 79(9).
-
T Adams,
J A Appel,
K E Arms,
A. B. Balantekin,
J. M. Conrad, P. S. Cooper,
Z. Djurcic,
W Dunwoodie,
J. Engelfried,
P H Fisher, [......],
H Ray,
J Russ,
A. J. Schwartz,
W. G. Seligman,
M. H. Shaevitz,
H Schellman,
J. Spitz,
M. J. Syphers,
T. M. P. Tait,
F. Vannucci
[show abstract]
[hide abstract]
ABSTRACT: This document describes the physics potential of a new fixed-target program based on a ~1 TeV proton source. Two proton sources are potentially available in the future: the existing Tevatron at Fermilab, which can provide 800 GeV protons for fixed-target physics, and a possible upgrade to the SPS at CERN, called SPS+, which would produce 1 TeV protons on target. In this paper we use an example Tevatron fixed-target program to illustrate the high discovery potential possible in the charm and neutrino sectors. We highlight examples which are either unique to the program or difficult to accomplish at other venues. Comment: 31 pages, 11 figures
05/2009;
-
E949 Collaboration,
A V Artamonov,
B Bassalleck,
B Bhuyan,
E. W. Blackmore,
D. A. Bryman,
S Chen,
I-H. Chiang,
I.A. Christidi, P. S. Cooper, [......],
S Sugimoto,
Y Tamagawa,
R Tschirhart,
T. Tsunemi,
D V Vavilov,
B. Viren,
Zhe Wang,
N. V. Yershov,
Y Yoshimura,
T Yoshioka
[show abstract]
[hide abstract]
ABSTRACT: Experiment E949 at Brookhaven National Laboratory has observed three new events consistent with the decay K+ => pi+,nu,nubar in the pion momentum region 140 < P_pi < 199 MeV/c in an exposure of 1.71e12 stopped kaons with an estimated total background of 0.93+-0.17(stat.)+0.32-0.24(syst.) events. This brings the total number of observed K+ => pi+,nu,nubar events to seven. Combining this observation with previous results, assuming the pion spectrum predicted by the standard model, results in a branching ratio of (1.73+1.15-1.05)e-10. An interpretation of the results for alternative models of the decay K^ => pi+,nothing is also presented. Comment: Submitted to Phys.Rev. D
02/2009;
-
A V Artamonov,
B Bassalleck,
B Bhuyan,
E W Blackmore,
D A Bryman,
S Chen,
I-H Chiang,
I-A Christidi, P S Cooper,
M V Diwan, [......],
S Sugimoto,
Y Tamagawa,
R Tschirhart,
T Tsunemi,
D V Vavilov,
B Viren,
Zhe Wang,
N V Yershov,
Y Yoshimura,
T Yoshioka
[show abstract]
[hide abstract]
ABSTRACT: Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 < Ppi < 199 MeV/c, with an estimated background of 0.93+/-0.17(stat.) -0.24+0.32(syst.) events. Combining this observation with previously reported results yields a branching ratio of B(K+-->pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.
Physical Review Letters 11/2008; 101(19):191802. · 7.37 Impact Factor
-
Selex Collaboration,
E. Vázquez-Jáuregui,
J. Engelfried,
U. Akgun,
G. Alkhazov,
J. Amaro-Reyes,
A. G. Atamantchouk,
A. S. Ayan,
M. Y. Balatz,
A. Blanco-Covarrubias, [......],
D. V. Vavilov,
V. S. Verebryusov,
V. A. Victorov,
V. E. Vishnyakov,
A. A. Vorobyov,
K. Vorwalter,
J. You,
Wenheng Zhao,
Shuchen Zheng,
R. Zukanovich-Funchal
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of two Cabibbo-suppressed decay modes,
Ξc+→Σππ and
Ξc+→Σππ. We observe
59±14 over a background of 87, and 22±8 over a background
of 13 events, respectively, for the signals. The data were accumulated
using the SELEX spectrometer during the 1996 1997 fixed target run at
Fermilab, chiefly from a 600GeV/cΣ beam. The branching
ratios of the decays relative to the Cabibbo-favored
Ξc+→Ξππ are measured
to be
B(Ξc+→Σππ)/B(Ξc+→Ξππ)=0.48±0.20,
and
B(Ξc+→Σππ)/B(Ξc+→Ξππ)=0.18±0.09,
respectively. We also report branching ratios for the same decay modes
of the Λc+ relative to
Λc+→pKπ.
Physics Letters B 08/2008; 666:299-304. · 3.95 Impact Factor
-
E. Behnke,
J. I. Collar, P. S. Cooper,
K. Crum,
M. Crisler,
M. Hu,
I Levine,
D. Nakazawa,
H Nguyen,
B. Odom,
E. Ramberg,
J. Rasmussen,
N. Riley,
A. Sonnenschein,
M. Szydagis,
R Tschirhart
[show abstract]
[hide abstract]
ABSTRACT: Bubble Chambers provided the dominant particle detection technology in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on the first period of operation of an ultra-clean, room-temperature bubble chamber containing 1.5 kg of superheated CF$_{3}$I, a target maximally sensitive to spin-dependent and -independent Weakly Interacting Massive Particle (WIMP) couplings. An exposure in excess of 250 kg-days is obtained, with a live-time fraction reaching 80%. This illustrates the ability to employ bubble chambers in a new realm, the search for dark matter particles. Improved limits on the spin-dependent WIMP-proton scattering cross section are extracted from this first period. An extreme intrinsic insensitivity to the backgrounds commonly limiting these experiments (a rejection factor for photon-induced electrons of $\sim10^{-10}$) has been measured in operating conditions leading to the detection of low-energy nuclear recoils such as those expected from WIMPs. Comment: This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science 319, 15 February 2008, doi:10.1126/science.1149999
04/2008;
-
S. Adler,
V. V. Anisimovsky,
M. Aoki,
M. Ardebili,
A. V. Artamonov,
M. Atiya,
B. Bassalleck,
A. O. Bazarko,
B. Bhuyan,
E. W. Blackmore, [......],
R. C. Strand,
S. Sugimoto,
Y. Tamagawa,
R. Tschirhart,
T. Tsunemi,
D. V. Vavilov,
B. Viren,
N. V. Yershov,
Y. Yoshimura,
T. Yoshioka
[show abstract]
[hide abstract]
ABSTRACT: Experiment E949 at Brookhaven National Laboratory studied the rare decay K+→π+νν̅ and other processes with an exposure of 1.77×1012 K+’s. The data were analyzed using a blind analysis technique yielding one candidate event with an estimated background of 0.30±0.03 events. Combining this result with the observation of two candidate events by the predecessor experiment E787 gave the branching ratio B(K+→π+νν̅ )=(1.47-0.89+1.30)×10-10, consistent with the standard model prediction of (0.74±0.20)×10-10. This is a more detailed report of results previously published [ V. V. Anisimovsky et al. Phys. Rev. Lett. 93 031801 (2004)].
Phys. Rev. D. 03/2008; 77(5).
-
E Behnke,
J I Collar, P S Cooper,
K Crum,
M Crisler,
M Hu,
I Levine,
D Nakazawa,
H Nguyen,
B Odom,
E Ramberg,
J Rasmussen,
N Riley,
A Sonnenschein,
M Szydagis,
R Tschirhart
[show abstract]
[hide abstract]
ABSTRACT: Bubble chambers were the dominant technology used for particle detection in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on a new application for these devices. We operated an ultraclean, room-temperature bubble chamber containing 1.5 kilograms of superheated CF3I, a target maximally sensitive to spin-dependent and -independent weakly interacting massive particle (WIMP) couplings. An extreme intrinsic insensitivity to the backgrounds that commonly limit direct searches for dark matter was measured in this device under operating conditions leading to the detection of low-energy nuclear recoils like those expected from WIMPs. Improved limits on the spin-dependent WIMP-proton scattering cross section were extracted during our experiments, excluding this type of coupling as a possible explanation for a recent claim of particle dark-matter detection.
Science 03/2008; 319(5865):933-6. · 31.20 Impact Factor
-
M. Iori,
A.S. Ayan,
U. Akgun,
G. Alkhazov,
J. Amaro-Reyes,
A.G. Atamantchouk,
M.Y. Balatz,
A. Blanco-Covarrubias,
N.F. Bondar, P.S. Cooper,
L.J. Dauwe
[show abstract]
[hide abstract]
ABSTRACT: The authors report a precise measurement of the {Omega}{sub c}{sup 0} lifetime. The data were taken by the SELEX (E781) experiment using 600 GeV/c {Sigma}{sup -}, {pi}{sup -} and p beams. The measurement has been made using 83 {+-} 19 reconstructed {Omega}{sub c}{sup 0} in the {Omega}{sup -} {pi}{sup -}{pi}{sup +}{pi}{sup +} and {Omega}{sup -} {pi}{sup +} decay modes. The lifetime of the {Omega}{sub c}{sup 0} is measured to be 65 {+-} 13(stat) {+-} 9(sys) fs.
12/2006;
-
A. V. Artamonov,
B. Bassalleck,
B. Bhuyan,
E. W. Blackmore,
D. A. Bryman,
S. Chen,
I.-H. Chiang,
I.-A. Christidi, P. S. Cooper,
M. V. Diwan, [......],
R. C. Strand,
S. Sugimoto,
Y. Tamagawa,
R. Tschirhart,
T. Tsunemi,
D. V. Vavilov,
B. Viren,
N. V. Yershov,
Y. Yoshimura,
T. Yoshioka
[show abstract]
[hide abstract]
ABSTRACT: A sample of kinematically identified
K+→π+π0 decays obtained with
the E949 detector was used to search for the helicity-suppressed decay
π0→νν¯ resulting in an upper limit of
2.7×10-7 at 90% confidence level. The upper limit is
also applicable to π0 decays into unknown
weakly-interacting particles.
Physical review D: Particles and fields 10/2005; 72(9):91102.
-
M. G. Albrow,
S. Antusch,
K. S. Babu,
T. Barnes,
A O Bazarko,
R. H. Bernstein,
T. J. Bowles,
S. J. Brice,
A Ceccucci,
F Cei, [......],
M. Lindner,
M. Mandelkern,
W. J. Marciano,
W. Melnitchouk,
O. Mena,
D. G. Michael,
J. P. Miller,
G B Mills,
J. G. Morfin,
H Nguyen
[show abstract]
[hide abstract]
ABSTRACT: This report documents the physics case for building a 2 MW, 8 GeV superconducting linac proton driver at Fermilab.
10/2005;
-
A V Evdokimov,
U Akgun,
G Alkhazov,
J Amaro-Reyes,
A G Atamantchouk,
A S Ayan,
M Y Balatz,
N F Bondar, P S Cooper,
L J Dauwe, [......],
E Vázquez-Jáuregui,
V S Verebryusov,
V A Victorov,
V E Vishnyakov,
A A Vorobyov,
K Vorwalter,
J You,
Zhao Wenheng,
Zheng Shuchen,
R Zukanovich-Funchal
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of a charm-strange meson D(+)(sJ)(2632) at a mass of 2632.5+/-1.7 MeV/c(2) in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, D(+)(s)eta and D0K+. In the D(+)(s)eta decay mode we observe a peak with 101 events over a combinatoric background of 54.9 events at a mass of 2635.4+/-3.3 MeV/c(2). There is a corresponding peak of 21 events over a background of 6.9 at 2631.5+/-2.0 MeV/c(2) in the decay mode D0K+. The decay width of this state is <17 MeV/c(2) at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(D(+)(s)eta) is 0.14+/-0.06. The mechanism that keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the D(+)(s)eta decay mode.
Physical Review Letters 12/2004; 93(24):242001. · 7.37 Impact Factor
-
V V Anisimovsky,
A V Artamonov,
B Bassalleck,
B Bhuyan,
E W Blackmore,
D A Bryman,
S Chen,
I-H Chiang,
I-A Christidi, P S Cooper, [......],
R C Strand,
S Sugimoto,
Y Tamagawa,
R Tschirhart,
T Tsunemi,
D V Vavilov,
B Viren,
N V Yershov,
Y Yoshimura,
T Yoshioka
[show abstract]
[hide abstract]
ABSTRACT: An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9.
Physical Review Letters 07/2004; 93(3):031801. · 7.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We present the design of two velocity spectrometers, to be used in the recently approved CKM experiment. CKM's main goal is the measurement of the branching ratio of K+ -> pi+ nu nu with a precision of 10%, via decays in flight of the K+. The design of both RICH detectors is based on the SELEX Phototube RICH. We will discuss the design and the expected performance, based on studies with SELEX data and Monte Carlo Simulations.
10/2002;
-
M Mattson,
G Alkhazov,
A G Atamantchouk,
M Y Balatz,
N F Bondar, P S Cooper,
L J Dauwe,
G V Davidenko,
U Dersch,
A G Dolgolenko, [......],
D V Vavilov,
V S Verebryusov,
V A Victorov,
V E Vishnyakov,
A A Vorobyov,
K Vorwalter,
J You,
Zhao Wenheng,
Zheng Shuchen,
R Zukanovich-Funchal
[show abstract]
[hide abstract]
ABSTRACT: We observe a signal for the doubly charmed baryon Xi(+)(cc) in the charged decay mode Xi(+)(cc)-->Lambda(+)(c)K-pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1+/-0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is 3519+/-1 MeV/c(2). The Gaussian mass width of this state is 3 MeV/c(2), consistent with resolution; its lifetime is less than 33 fs at 90% confidence.
Physical Review Letters 09/2002; 89(11):112001. · 7.37 Impact Factor
