# Dorian Kcira's research while affiliated with California Institute of Technology and other places

## Publications (34)

Article
Full-text available
Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the she...
Article
Full-text available
Machine learning is an important applied research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle and event identification and reconstruction in the 2010s. In this document we discuss promising future research and development areas in m...
Article
Full-text available
Machine learning is an important applied research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle and event identification and reconstruction in the 2010s. In this document we discuss promising future research and development areas in m...
Preprint
Full-text available
Machine learning is an important research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle and event identification and reconstruction in the 2010s. In this document we discuss promising future research and development areas in machine l...
Conference Paper
Full-text available
The massive data volumes acquired, simulated, processed and analyzed by globally distributed scientific collaborations continue to grow exponentially. One leading example is the LHC program, now at the start of its second three year data taking cycle, searching for new particles and interactions in a previously inaccessible range of energies, which...
Article
Full-text available
The physics event reconstruction is one of the biggest challenges for the computing of the LHC experiments. Among the different tasks that computing systems of the CMS experiment performs, the reconstruction takes most of the available CPU resources. The reconstruction time of single collisions varies according to event complexity. Measurements wer...
Conference Paper
During Supercomputing 2012 (SC12), an international team of high energy physicists, computer scientists, and network engineers led by the California Institute of Technology (Caltech), the University of Victoria, and the University of Michigan, together with Brookhaven National Lab, Vanderbilt and other partners, smashed their previous records for d...
Article
We present a data transfer system for the grid environment built on top of the open source FDT tool (Fast Data Transfer) developed by Caltech in collaboration with the National University of Science and Technology (Pakistan). The enhancement layer above FDT consists of a client program - fdtcp (FDT copy) and a fdtd service (FDT daemon). This pair o...
Article
The vast majority of the CMS Computing capacity, which is organized in a tiered hierarchy, is located away from CERN. The 7 Tier-1 sites archive the LHC proton-proton collision data that is initially processed at CERN. These sites provide access to all recorded and simulated data for the Tier-2 sites, via wide-area network (WAN) transfers. All cent...
Article
Full-text available
A measurement of the angular correlations between beauty and anti-beauty hadrons (B B-bar) produced in pp collisions at a centre-of-mass energy of 7 TeV at the CERN LHC is presented, probing for the first time the region of small angular separation. The B hadrons are identified by the presence of displaced secondary vertices from their decays. The...
Article
Full-text available
The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The $${\text{K}}_{\text{S}}^0$$, Λ, and Ξ− particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapid...
Article
Full-text available
Hadronic event shapes have been measured in proton-proton collisions at sqrt(s)=7 TeV, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 inverse picobarns. Event-shape distributions, corrected for detector response, are compared with five models of QCD multijet production.
Article
Full-text available
A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 inverse picobarns collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic...
Article
Full-text available
A search for microscopic black hole production and decay in pp collisions at a center-of-mass energy of 7 TeV has been conducted by the CMS Collaboration at the LHC, using a data sample corresponding to an integrated luminosity of 35 inverse picobarns. Events with large total transverse energy are analyzed for the presence of multiple high-energy j...
Article
Full-text available
The differential cross section for the inclusive production of isolated prompt photons has been measured as a function of the photon transverse energy E_T-gamma in pp collisions at sqrt(s)=7 TeV using data recorded by the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.9 inverse picobarns. Photons are required...
Article
Full-text available
A measurement of the b-hadron production cross section in proton-proton collisions at $$\sqrt {s} = 7\;{\text{TeV}}$$ is presented. The dataset, corresponding to 85 nb−1, was recorded with the CMS experiment at the LHC using a low-threshold single-muon trigger. Events are selected by the presence of a muon with transverse momentum \( p_T^\mu > 6\...
Article
Full-text available
A search for pair production of first-generation scalar leptoquarks is performed in the final state containing two electrons and two jets using proton-proton collision data at sqrt(s)=7 TeV. The data sample used corresponds to an integrated luminosity of 33 inverse picobarns collected with the CMS detector at the CERN LHC. The number of observed ev...
Article
Full-text available
The results of the first search for long-lived gluinos produced in 7 TeV pp collisions at the CERN Large Hadron Collider are presented. The search looks for evidence of long-lived particles that stop in the CMS detector and decay in the quiescent periods between beam crossings. In a dataset with a peak instantaneous luminosity of 10^{32} cm^{-2} s^...
Article
Full-text available
The Upsilon production cross section in proton-proton collisions at $\sqrt{s}$ = 7 TeV is measured using a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 3.1 +/- 0.3 inverse picobarns. Integrated over the rapidity range |y|<2, we find the product of the Upsilon(1S) production cross section and b...
Article
Full-text available
Measurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s) = 7 TeV are presented, based on 2.9 pb-1 of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp --> WX) X B(W--> ln) = 9.95 +/- 0.07 (stat.) +/- 0.28 (syst.) +/- 1...
Article
Full-text available
The result of a search at the LHC for heavy stable charged particles produced in pp collisions at sqrt(s) = 7 TeV is described. The data sample was collected with the CMS detector and corresponds to an integrated luminosity of 3.1 inverse picobarns. Momentum and ionization-energy-loss measurements in the inner tracker detector are used to identify...
Article
Full-text available
Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at $\sqrt{s}$ = 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 inverse picobarns. The data are found to be in good agreement with the predictions of perturbative QCD, and yiel...
Article
Full-text available
Measurements of the total and differential cross sections with respect to transverse momentum and rapidity for B+ mesons produced in pp collisions at $\sqrt{s}$ = 7 TeV are presented. The data correspond to an integrated luminosity of 5.8 inverse picobarns collected by the CMS experiment operating at the LHC. The exclusive decay $B^+ \to J/\psi K^+... Article Full-text available A measurement of the underlying activity in scattering processes with pT scale in the GeV region is performed in proton-proton collisions at$\sqrt{s}$= 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged hadron production is studied with reference to the direction of a leading object, either a charged particle or a set of char... Article Full-text available A search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9 inverse pb collected by the CMS experiment at the LHC. Upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separatel... Article Full-text available We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/c to 1 TeV/C. The surface flux ratio is measured to b... Article Full-text available Bose-Einstein correlations have been measured using samples of proton-proton collisions at 0.9 and 2.36 TeV center-of-mass energies, recorded by the CMS experiment at the CERN Large Hadron Collider. The signal is observed in the form of an enhancement of pairs of same-sign charged particles with small relative four-momentum. The size of the correla... Article Full-text available Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at$\sqrt{s} = 7$~TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit-pairs, and fully reconstructed charged-particle tracks. The combinati... Article Full-text available The first LHC pp collisions at centre-of-mass energies of 0.9 and 2.36 TeV were recorded by the CMS detector in December 2009. The trajectories of charged particles produced in the collisions were reconstructed using the all-silicon Tracker and their momenta were measured in the 3.8 T axial magnetic field. Results from the Tracker commissioning are... Article Full-text available A search for quark compositeness in the form of quark contact interactions, based on hadronic jet pairs (dijets) produced in proton-proton collisions at sqrt(s)=7 TeV, is described. The data sample of the study corresponds to an integrated luminosity of 2.9 inverse picobarns collected with the CMS detector at the LHC. The dijet centrality ratio, wh... Article Full-text available Results on two-particle angular correlations for charged particles emitted in proton-proton collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV are presented, using data collected with the CMS detector over a broad range of pseudorapidity (eta) and azimuthal angle ($\phi$). Short-range correlations in$\Delta\eta\$, which are studied in mi...
Conference Paper
Full-text available
Data distribution, storage and access are essential to CPU-intensive and data-intensive high performance Grid computing. A newly emerged file system, Hadoop distributed file system (HDFS), is deployed and tested within the Open Science Grid (OSG) middleware stack. Efforts have been taken to integrate HDFS with other Grid tools to build a complete s...
Article
Full-text available
In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to...

## Citations

... Limiting the increase of computing resource consumption at large pileup is a necessary step for the success of the HL-LHC physics program [1]. The use of modern machine learning techniques to perform particle reconstruction has been advocated as a possible solution to this problem [3]. ...
... With powerful machine learning (especially deep learning) algorithms, new physics analyses have been enabled and established ones report improved results over previous iterations that utilized only cut-based strategies, shallow networks or techniques like BDTs [1]. For object identification, which serves as a crucial ingredient to various analyses carried out at experiments at the CERN Large Hadron Collider, it is therefore of prime interest to provide highly-performant algorithms, where many features enter complex architectures to capture as much information as possible, including correlations between observables. ...
... 75 3. 10 The examples figures 75 3.11 Relative difference between PDFFlow and LHAPDF (same as 3.5) for the MMHT2014 NLO set for all flavors. 77 4. 1 The MadFlow tool-suite includes all the needed ingredients for MC event generation on hardware accelerators: on top of the VegasFlow MC integrator, the GPU phase space generator constructs physical points to be fed in the computation of the luminosity factor done with PDFFlow and the evaluation of the partonic cross sectionσ through the ME computation. ...
... To the best of our knowledge, this is the first work that explores resource reservation in the context of ICN. The motivation for our work came from deadline based large scientific data transfers [6] [7] [3] and as a result, the scope of this particular study is confined to large scientific data transfers over single-domain science networks such as Internet2 or ESNet. For now, we do not consider inter-domain reservations which can introduce a large number of operational challenges such as traffic engineering policies, peering, and economic incentives [9]. ...
... NASA Goddard has demonstrated 115 Gbps in back to back memory-to-memory testing, and 96 Gbps disk-to-disk tests using SSD drives [6]. Caltech has reported 80 Gbps with a single host [11], and in our own testing we have seen similar performance. ...
... OvS provides quality of service (QoS) and traffic shaping right at the end-point of a data transfer. QoS via OvS is protocol agnostic: one can use TCP (GridFTP [11], FDT [12]) or UDP. The use of OvS helps to achieve better throughput by moderating and stabilizing data flows; e.g. in cases where the upstream switches have limited buffer memory. ...
... File System) runs on general hardware (so-called universal hardware)Hardware means that the software has no requirements for the configuration and equipment of the underlying hardware platform, so it can be freely built and compatible [1][2]. For HDFS file system, including the overall Hadoop components, this can achieve perfect expansibility. ...
Citing conference paper
... This clear division of tasks was questioned by data from LHC. First in 2010, with the discovery of long-range azimuthal correlations of final-state hadrons in high multiplicity pp collisions, referred to as "the near-side ridge" [341], and later by observations of enhanced production of strange and multi-strange final-state hadrons, incompatible with model fits to LEP data [342][343][344][345]. The latter culminated in the observation that not only is the observed strangeness production incompatible with model fits to LEP data, strange/non-strange ratios also increase with multiplicity, and the increase smoothly connects pp with pA and AA collision systems [346]. ...
... Ratios of jet p T spectra [25] CMS 2013 I1224539 DIJET Jet mass measurement in dijet events [26] CMS 2013 I1208923 Jet p T and dijet mass [27] CMS 2012 I1184941 Inclusive dijet production as a function of ξ [28] CMS 2012 I1090423 Dijet angular distributions [29] CMS 2012 I1087342 Forward and forward + central jets [30] CMS 2011 S9215166 Forward energy flow in dijet events [31] CMS 2011 S9088458 Ratio of 3-jet over 2-jet cross-sections [32] CMS 2011 S9086218 Inclusive jet cross-section [33] CMS 2011 S8968497 Dijet angular distributions [34] CMS 2011 S8950903 Dijet azimuthal decorrelations [35] schemes consider hardness relative to partons other than the emitter and take the smallest, they will in general produce lower hardness scales for proposed shower emissions and hence fewer such emissions will be vetoed. ...
... The analysis to study the event shapes is well known for leptonic collisions [9,10,11] and also present fascinating features in hadronic collisions, in particular underlying event characterization, effects of hadronization and comparison of perturbative QCD (pQCD) computations with high ! jets [12,13,14,15]. Event shape observables are confined to the plane perpendicular to the beam axis at hadron collider to avoid bias from the boost. ...