-
[show abstract]
[hide abstract]
ABSTRACT: Sparse matrix matrix (SpMM) multiplication is involved in a wide range of scientific and technical
applications. The computational requirements for this kind of operation are enormous, especially
for large matrices. This paper analyzes and evaluates a method to efficiently compute the SpMM
product in a computing environment that includes graphics processing units (GPUs). Some libraries
tocomputethismatricialoperationcanbefoundintheliterature.However,ourstrategy(FastSpMM)
outperforms the existing approaches because it combines the use of the ELLPACK-R storage format
with the exploitation of the high ratio computation/memory access of the SpMM operation and the
overlapping of CPU–GPU communications/computations by Compute Unified Device Architecture
streaming computation. In this work, FastSpMM is described and its performance evaluated with
regard to the CUSPARSE library (supplied by NVIDIA), which also includes routines to compute
SpMM on GPUs. Experimental evaluations based on a representative set of test matrices show that, in
termsofperformance,FastSpMMoutperformstheCUSPARSEroutineaswellastheimplementation
of the SpMM as a set of sparse matrix vector products.
The Computer Journal 05/2014; · 0.79 Impact Factor
-
CDF Collaboration,
T. Aaltonen,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel,
T. Arisawa, [......],
K. Yi,
J. Yoh,
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
A. M. Zanetti,
Y. Zeng,
C. Zhou,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report on a measurement of the top-quark electric charge in ttbar events
in which one W boson originating from the top-quark pair decays into leptons
and the other into hadrons. The event sample was collected by the CDF II
detector in sqrt(s)=1.96 TeV proton-antiproton collisions and corresponds to
5.6 fb^(-1). We find the data to be consistent with the standard model and
exclude the existence of an exotic quark with -4/3 electric charge and mass of
the conventional top quark at the 99% confidence level.
04/2013;
-
T Aaltonen,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa,
A Artikov, [......],
K Yi,
J Yoh,
K Yorita,
T Yoshida,
G B Yu,
I Yu,
A M Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: This Letter reports a measurement of the cross section for producing pairs of central prompt isolated photons in proton-antiproton collisions at a total energy sqrt[s]=1.96 TeV using data corresponding to 9.5 fb^{-1} integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. The measured differential cross section is compared to three calculations derived from the theory of strong interactions. These include a prediction based on a leading order matrix element calculation merged with a parton shower model, a next-to-leading order calculation, and a next-to-next-to-leading order calculation. The first and last calculations reproduce most aspects of the data, thus showing the importance of higher-order contributions for understanding the theory of strong interaction and improving measurements of the Higgs boson and searches for new phenomena in diphoton final states.
Physical Review Letters 03/2013; 110(10):101801. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present the first direct measurement of the top-quark mass using tt[over ¯] events decaying in the hadronic τ+jets decay channel. Using data corresponding to an integrated luminosity of 2.2 fb^{-1} collected by the CDF II detector in pp[over ¯] collisions at sqrt[s]=1.96 TeV at the Fermilab Tevatron, we measure the tt[over ¯] cross section, σ_{tt[over ¯]}, and the top-quark mass, M_{top}. We extract M_{top} from a likelihood based on per-event probabilities calculated with leading-order signal and background matrix elements. We measure σ_{tt[over ¯]}=8.8±3.3(stat)±2.2(syst) pb and M_{top}=172.7±9.3(stat)±3.7(syst) GeV/c^{2}.
Physical Review Letters 11/2012; 109(19):192001. · 7.37 Impact Factor
-
CDF Collaboration,
T. Aaltonen,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel,
T. Arisawa, [......],
K. Yi,
J. Yoh,
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
A. M. Zanetti,
Y. Zeng,
C. Zhou,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present new measurements of the inclusive forward-backward ttbar
production asymmetry, AFB, and its dependence on several properties of the
ttbar system. The measurements are performed with the full Tevatron data set
recorded with the CDF II detector during ppbar collisions at sqrt(s) = 1.96
TeV, corresponding to an integrated luminosity of 9.4 fb^(-1). We measure the
asymmetry using the rapidity difference Delta-y=y_(t)-y_(tbar). Parton-level
results are derived, yielding an inclusive asymmetry of 0.164+/-0.047 (stat +
syst). We observe a linear dependence of AFB on the top-quark pair mass
M(ttbar) and the rapidity difference |Delta-y| at detector and parton levels.
Assuming the standard model, the probabilities to observe the measured values
or larger for the detector-level dependencies are 7.4*10^(-3) and 2.2*10^(-3)
for M(ttbar) and |Delta-y| respectively. Lastly, we study the dependence of the
asymmetry on the transverse momentum of the ttbar system at the detector level.
These results are consistent with previous lower-precision measurements and
provide additional quantification of the functional dependencies of the
asymmetry.
11/2012;
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: A search is presented for the standard model Higgs boson produced in association with top quarks using the full Run II proton-antiproton collision data set, corresponding to 9.45 fb^{-1}, collected by the Collider Detector at Fermilab. No significant excess over the expected background is observed, and 95% credibility-level upper bounds are placed on the cross section σ(tt[over ¯]H→lepton+missing transverse energy+jets). For a Higgs boson mass of 125 GeV/c^{2}, we expect to set a limit of 12.6 and observe a limit of 20.5 times the standard model rate. This represents the most sensitive search for a standard model Higgs boson in this channel to date.
Physical Review Letters 11/2012; 109(18):181802. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the bottom-strange meson mixing phase β_{s} using the time evolution of B_{s}^{0}→J/ψ(→μ^{+}μ^{-})ϕ(→K^{+}K^{-}) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt[s]=1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb^{-1} of integrated luminosity. We report confidence regions in the two-dimensional space of β_{s} and the B_{s}^{0} decay-width difference ΔΓ_{s} and measure β_{s}∈[-π/2,-1.51]∪[-0.06,0.30]∪[1.26,π/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of β_{s}, we also determine ΔΓ_{s}=0.068±0.026(stat)±0.009(syst) ps^{-1} and the mean B_{s}^{0} lifetime τ_{s}=1.528±0.019(stat)±0.009(syst) ps, which are consistent and competitive with determinations by other experiments.
Physical Review Letters 10/2012; 109(17):171802. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a precision measurement of the top-quark mass using the full sample of Tevatron sqrt[s]=1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb^{-1}. Using a sample of tt[over ¯] candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, M_{top}=172.85±0.71(stat)±0.85(syst) GeV/c^{2}.
Physical Review Letters 10/2012; 109(15):152003. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb^{-1}. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H→bb[over ¯] branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^{2}, we observe (expect) a limit of 7.1 (3.9) times the standard model value.
Physical Review Letters 09/2012; 109(11):111803. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We combine the results of searches for the standard model (SM) Higgs boson based on the full CDF Run II data set obtained from sqrt[s]=1.96 TeV pp[over ¯] collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45 fb^{-1}. The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150 GeV/c^{2}, and decay into bb[over ¯] pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).
Physical Review Letters 09/2012; 109(11):111802. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the standard model Higgs boson produced in association with a W boson in sqrt[s]=1.96 TeV pp[over ¯] collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb^{-1}. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H→bb[over ¯] branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^{2}, we observe (expect) a limit of 4.9 (2.8) times the standard model value.
Physical Review Letters 09/2012; 109(11):111804. · 7.37 Impact Factor
-
T Aaltonen,
B Alvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
T Arisawa, [......],
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
C Zhou,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at sqrt[s]=1.96 TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb^{-1}. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a b quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and 150 GeV/c^{2}. For a Higgs boson mass of 125 GeV/c^{2}, the observed (expected) limit is 6.7 (3.6) times the standard model prediction.
Physical Review Letters 09/2012; 109(11):111805. · 7.37 Impact Factor
-
T. Aaltonen,
B. Álvarez González,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel,
T. Arisawa, [......],
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
S. S. Yu,
J. C. Yun,
A. Zanetti,
Y. Zeng,
C. Zhou,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the standard model Higgs boson produced in association with a W± boson. This search uses data corresponding to an integrated luminosity of 7.5 fb-1 collected by the CDF detector at the Tevatron. We select WH→ℓνbb̅ candidate events with two jets, large missing transverse energy, and exactly one charged lepton. We further require that at least one jet be identified to originate from a bottom quark. Discrimination between the signal and the large background is achieved through the use of a Bayesian artificial neural network. The number of tagged events and their distributions are consistent with the standard model expectations. We observe no evidence for a Higgs boson signal and set 95% C.L. upper limits on the WH production cross section times the branching ratio to decay to bb̅ pairs, σ(pp̅ →W±H)×B(H→bb̅ ), relative to the rate predicted by the standard model. For the Higgs boson mass range of 100 to 150 GeV/c2 we set observed (expected) upper limits from 1.34 (1.83) to 38.8 (23.4). For 115 GeV/c2 the upper limit is 3.64 (2.78). The combination of the present search with an independent analysis that selects events with three jets yields more stringent limits ranging from 1.12 (1.79) to 34.4 (21.6) in the same mass range. For 115 and 125 GeV/c2 the upper limits are 2.65 (2.60) and 4.36 (3.69), respectively.
Phys. Rev. D. 08/2012; 86(3).
-
T. Aaltonen,
M. Albrow,
B. Álvarez González,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel, [......],
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
S. S. Yu,
J. C. Yun,
A. Zanetti,
Y. Zeng,
C. Zhou,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report on a study of diffractive dijet production in p̅ p collisions at √s=1.96 TeV using the CDF II detector at the Fermilab Tevatron p̅ p collider. A data sample from 310 pb-1 of integrated luminosity collected by triggering on a high transverse energy jet, ETjet, in coincidence with a recoil antiproton detected in a Roman pot spectrometer is used to measure the ratio of single-diffractive to inclusive-dijet event rates as a function of xp̅ of the interacting parton in the antiproton, the Bjorken-x, xBjp̅ , and a Q2≈(ETjet)2 in the ranges 10-3<xBjp̅ <10-1 and 102<Q2<104 GeV2, respectively. Results are presented for the region of p̅ -momentum-loss fraction 0.03<ξp̅ <0.09 and a four-momentum transfer squared tp̅ >-4 GeV2. The tp̅ dependence is measured as a function of Q2 and xBjp̅ and compared with that of inclusive single diffraction dissociation. We find weak xBjp̅ and Q2 dependencies in the ratio of single diffractive to inclusive event rates, and no significant Q2 dependence in the diffractive tp̅ distributions.
Phys. Rev. D. 08/2012; 86(3).
-
T. Aaltonen,
B. Álvarez González,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel,
T. Arisawa, [......],
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
S. S. Yu,
J. C. Yun,
A. Zanetti,
Y. Zeng,
C. Zhou,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0→KS0π+π- using CDF II data corresponding to 6.0 fb-1 of integrated luminosity from Tevatron pp̅ collisions at √s=1.96 TeV. The charm mesons used in this analysis come from D*+(2010)→D0π+ and D*-(2010)→D̅ 0π-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely, a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D̅ 0 Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP=(-0.05±0.57(stat)±0.54(syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.
Phys. Rev. D. 08/2012; 86(3).
-
T. Aaltonen,
B. Álvarez González,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel,
A. Apresyan, [......],
J. Yoh,
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
S. S. Yu,
J. C. Yun,
A. Zanetti,
Y. Zeng,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report a set of measurements of inclusive invariant pT differential cross sections of Λ0, Λ̅ 0, Ξ±, and Ω± hyperons reconstructed in the central region with pseudorapidity |η|<1 and pT up to 10 GeV/c. Events are collected with a minimum-bias trigger in pp̅ collisions at a center-of-mass energy of 1.96 TeV using the CDF II detector at the Tevatron Collider. As pT increases, the slopes of the differential cross sections of the three particles are similar, which could indicate a universality of the particle production in pT. The invariant differential cross sections are also presented for different charged-particle multiplicity intervals.
Phys. Rev. D. 07/2012; 86(1).
-
T Aaltonen,
B Álvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
A Apresyan, [......],
J Yoh,
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
S Zucchelli
Phys. Rev. D. 07/2012; 86(1):012002.
-
T. Aaltonen,
B. Álvarez González,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
J. A. Appel,
T. Arisawa, [......],
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
S. S. Yu,
J. C. Yun,
A. Zanetti,
Y. Zeng,
C. Zhou,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: Using data from pp̅ collisions at √s=1.96 TeV recorded by the CDF II detector at the Fermilab Tevatron, we present improved measurements of the masses and first measurements of natural widths of the four bottom baryon resonance states Σb+, Σb*+ and Σb-, Σb*-. These states are fully reconstructed in their decay modes to Λb0π± where Λb0→Λc+π- with Λc+→pK-π+. The analysis is based on a data sample corresponding to an integrated luminosity of 6.0 fb-1 collected by an online event selection based on tracks displaced from the pp̅ interaction point.
Phys. Rev. D. 05/2012; 85(9).
-
T Aaltonen,
B Álvarez González,
S Amerio,
D Amidei,
A Anastassov,
A Annovi,
J Antos,
G Apollinari,
J A Appel,
A Apresyan, [......],
J Yoh,
K Yorita,
T Yoshida,
G B Yu,
I Yu,
S S Yu,
J C Yun,
A Zanetti,
Y Zeng,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report on a search for the standard model Higgs boson decaying into pairs of τ leptons in pp collisions produced by the Tevatron at sqrt[s]=1.96 TeV. The analyzed data sample was recorded by the CDFII detector and corresponds to an integrated luminosity of 6.0 fb(-1). The search is performed in the final state with one τ decaying leptonically and the second one identified through its semihadronic decay. Since no significant excess is observed, a 95% credibility level upper limit on the production cross section times branching ratio to the ττ final state is set for hypothetical Higgs boson masses between 100 and 150 GeV/c2. For a Higgs boson of 120 GeV/c2 the observed (expected) limit is 14.6 (15.3) the predicted value.
Physical Review Letters 05/2012; 108(18):181804. · 7.37 Impact Factor
-
The CDF Collaboration,
T. Aaltonen,
B. ÁlvarezGonzález,
S. Amerio,
D. Amidei,
A. Anastassov,
A. Annovi,
J. Antos,
G. Apollinari,
A. Apresyan, [......],
J. Yoh,
K. Yorita,
T. Yoshida,
G. B. Yu,
I. Yu,
S. S. Yu,
J. C. Yun,
A. Zanetti,
Y. Zeng,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set
acquired with the CDF detector. Based on this improved estimate, we show that the total number and the properties of the collected
dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in
the data, of heavy flavor, ϒ, and Drell–Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds
to (12.8±3.2)% of the b[`(b)]b\bar{b} production. We find that (23±6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction
is (6.9±0.4)% for events due to b[`(b)]b\bar{b} production.
European Physical Journal C 05/2012; 71(8):1-14. · 3.63 Impact Factor
