Search results

Title: Polarised Drell-Yan physics at COMPASS, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Franco, Celso
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: The COMPASS experiment at CERN is one of the leading experiments studying the spin structure of the nucleon. Until now, the Parton...
Show moreThe COMPASS experiment at CERN is one of the leading experiments studying the spin structure of the nucleon. Until now, the Parton Distribution Functions (PDFs) and the Transverse Momentum Dependent Parton Distribution Functions (TMD PDFs) of protons and deuterons have been studied in Semi-Inclusive Deep Inelastic Scattering (SIDIS) measurements. The polarised Drell-Yan (DY) process is a complementary way to access the TMD PDFs, as it allows us to measure convolutions of only PDFs without involving fragmentation functions (FFs). COMPASS aims to perform the first ever polarised DY experiment in the world, which is foreseen to start in late 2014. By detecting dimuons from DY events we will be able to extract azimuthal spin asymmetries, each containing a convolution of two TMD PDFs, one from a negative pion beam with a momentum of 190 GeV/c and the other one from a transversely polarised proton target (NH₃). After their disentangling we can access four of the eight TMD PDFs needed to describe the nucleon structure at leading twist, like the Sivers and the Boer-Mulders functions. The opportunity to study, in the same experiment, the TMD PDFs from both SIDIS and DY processes is unique at COMPASS. Therefore, we are in privileged conditions to confirm or to deny the expected sign change in Sivers and Boer-Mulders functions when accessed via DY or SIDIS processes. An overview of the preparation and future measurements of the polarised DY experiment will be provided.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Measurement of anisotropic radial flow rapidity, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Wu, Yuafang, Li, Lin, Li, Na
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: Using the sample of Au + Au collisions at 200 GeV generated by the AMPT with string melting model, the anisotropic amplitudes of azimuthal...
Show moreUsing the sample of Au + Au collisions at 200 GeV generated by the AMPT with string melting model, the anisotropic amplitudes of azimuthal distributions of total transverse momentum, mean radial (transverse) momentum, and multiplicity are first presented and compared. It shows that the azimuthal distribution of mean radial momentum well characterizes the radial expansion. So a measurement of the azimuthal distribution of mean transverse (radial) rapidity of final state particles is suggested. We further show that the isotropic part of the suggested distribution is the combination of isotropic radial expansion and thermal motion. The anisotropic amplitude characterizes the anisotropic radial flow, and coincides with the parameter of anisotropic radial flow rapidity extracted from a generalized blast-wave parametrization.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

$Diffractive cross sections implemented in PYTHIA8-MBR VS LHC results$

Title: Diffractive cross sections implemented in PYTHIA8-MBR VS LHC results, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Goulianos, Konstantin
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: Diffractive cross sections implemented in the pythia8-mbr Monte Carlo simulation are reviewed and compared to results obtained at the Large...
Show moreDiffractive cross sections implemented in the pythia8-mbr Monte Carlo simulation are reviewed and compared to results obtained at the Large Hadron Collider.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: NEUTRON PRODUCTION IN THE M2 MUON BEAM LINE AT CERN
Creator: Draeger, Emily
Date: 2014, 2014-05
Description: Spallation neutrons produced from cosmic ray muons are a major source of backgrounds in underground physics experiments. Experiments have been...
Show moreSpallation neutrons produced from cosmic ray muons are a major source of backgrounds in underground physics experiments. Experiments have been done to study spallation neutron production and yield, but our understanding of these processes is still limited. There are various interactions that can produce spallation neutrons. Most of these production mechanisms are fairly well understood; much of the uncertainty in our understanding of spallation neutrons lies in mechanisms such as virtual photon exchange and the assumptions used to calculate the photonuclear cross section. Even the experiments that have been carried out do not agree with each other or theoretical calculations. Spallation neutron production mechanisms are discussed, as well as a new experiment to study spallation neutrons. The impact of this study on current and future underground physics experiments is also explored.
PH.D in Physics, May 2014
Show less

Title: DEVELOPMENT OF A HIGH ANGULAR RESOLUTION DIFFUSION IMAGING TEMPLATE AND PROBABILISTIC CONNECTIVITY-BASED ATLAS OF THE HUMAN BRAIN
Creator: Varentsova, Anna
Date: 2016, 2016-05
Description: Digital human brain atlases consisting of MRI-based templates and semantic labels delineating different brain regions serve a critical role in...
Show moreDigital human brain atlases consisting of MRI-based templates and semantic labels delineating different brain regions serve a critical role in neuroimaging, mainly facilitating spatial normalization and automated segmentation for the purposes of voxel-wise, region-of-interest, and network analyses. Diffusion MRI templates contain rich information about the microstructure of the brain, however the accuracy of templates constructed based on the diffusion tensor imaging (DTI) model is limited in regions with complex neuronal microarchitecture. High angular resolution diffusion imaging (HARDI) overcomes limitations of the DTI model and is capable of resolving intravoxel heterogeneity. In this work a method to develop artifact-free HARDI template of the human brain from low angular resolution data is presented. Existing white matter (WM) atlases have been generated either based on anatomical landmarks, thus mixing tracts with substantially different roles, or using DTI tractography, which fails in regions with crossing fibers. Connectivity-based atlases developed using HARDI templates and probabilistic tractography have potential to identify functionally distinct subregions of the brain. This work presents connectivity-based atlas of human brain WM created using HARDI template in ICBM-152 space and a set of FreeSurfer grey matter labels.
Ph.D. in Physics, May 2016
Show less

Title: FIELD AND PHOTO-EMISSION IN A SHORT-PULSE, HIGH-CHARGE CESIUM TELLURIDE RF PHOTOINJECTOR
Creator: Wisniewski, Eric E.
Date: 2014, 2014-05
Description: A new high-charge RF gun is now operating at the Argonne Wakefield Accelerator (AWA) facility at Argonne National Laboratory (ANL). The 1.5...
Show moreA new high-charge RF gun is now operating at the Argonne Wakefield Accelerator (AWA) facility at Argonne National Laboratory (ANL). The 1.5 cell 1.3 GHz gun uses a Cesium telluride photocathode driven with a 248 nm laser to provide short-pulse, high charge electron beams for the new 75 MeV drive beamline. The high-gradient RF gun (peak field on the cathode > 80MV/m) is a key piece of the facility upgrade. The large Cs2Te photocathode (diameter > 30 mm) was fabricated in-house. The photo-injector will be used to generate high-charge, short pulse, single bunches (Q > 100 nC) and bunch-trains (Q>1000 nC) for wakefield experiments, typically involving dielectric-loaded accelerating structures. Details of the photocathode fabrication process and the results of associated diagnostic measurements are presented, including QE measurements and work function measurements performed with a Kelvin probe. Field-emitted dark current from the Cs2Te cathode was measured during RF conditioning and characterized. Fowler-Nordheim plots of the data are presented and compared to similar measurements made using a copper cathode in the initial phase of conditioning. The results for cesium telluride exhibited non-linear regions within the Fowler-Nordheim plots similar to previous experimental results for other p-type semiconductors. Results of quantum efficiency (QE) studies are presented with the cathode operating in both single and bunch-train modes. QE uniformity and lifetime studies are presented. During commissioning, the cesium telluride photocathode produced bunch-charge of 100 nC, breaking the previous record. No evidence of bunch-train position-dependence of QE was found when generating four-bunch trains with total charge up to 200 nC.
PH.D in Physics, May 2014
Show less

Title: Searching for W' bosons at LHC with single top production, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Duffty, Daniel, Sullivan, Zack
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: One of the strengths of the LHC is its capacity for the discovery of new physics. As a consequence of many BSM theories, W′ bosons make an...
Show moreOne of the strengths of the LHC is its capacity for the discovery of new physics. As a consequence of many BSM theories, W′ bosons make an ideal particle to search for to constrain many models. One mode in particular has relatively low background: Single top quark production mediated by a W′ boson. For W′ masses less than 1500 GeV, all the decay products of the top quark are visible, and the strongest channel is the top’s decay into an electron or muon, with the associated neutrino and a bottom jet. As the W′ mass increases, the decay products from the highly boosted top and bottom quarks from the W′ appear as fat jets; boosted top tagging algorithms abound, and we propose a boosted bottom tag to set an exclusion limit of 2750 GeV for standard model-like couplings with existing 8 TeV data.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Physics implications of correlation data from the RHIC and LHC heavy-ion programs, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Ray, R. L.
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: Two-dimensional angular correlation data from the STAR experiment at RHIC and from the LHC experiments provide critical information about...
Show moreTwo-dimensional angular correlation data from the STAR experiment at RHIC and from the LHC experiments provide critical information about dynamical processes in relativistic heavy-ion collisions. The principal correlation structures of interest are a broad jet-related peak at small relative azimuth (φ) extending to large relative pseudorapidity (η), the dijet ridge at large relative azimuth, and an independent double ridge on φ represented by a quadrupole function. The broad peak at small relative azimuth has been attributed, in large part, to initial-state fluctuations and hydrodynamic flow which produce higher-order harmonics on φ. That conjecture is challenged in this paper. It is shown that the net effect of additional higher harmonic model elements is to describe small, non-Gaussian (NG) shapes in the broad jet-related peak. The quadrupole correlation, which is also conventionally attributed to hydrodynamic flow, is considered within the Balitsky - Fadin - Kuraev - Lipatov (BFKL) Pomeron framework. Preliminary results using this model for the quadrupole correlation for particle production from 200 GeV p + p collisions are shown to be consistent with recent data from STAR.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: STAR Results from the RHIC Beam Energy Scan, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Wang, Hui
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: The Beam Energy Scan Program is launched by RHIC to study the QCD phase diagram. The goal is to explore the possible QCD phase boundary and...
Show moreThe Beam Energy Scan Program is launched by RHIC to study the QCD phase diagram. The goal is to explore the possible QCD phase boundary and search for possible QCD critical point. In 2010 and 2011, experiments collected data at √sNN=7.7, 11.5, 19.6, 27, 39 and 62.4 GeV, covering a wide range of baryon chemical potential from μB 420 to 70 MeV. In this presentation, we will report some latest results of the Beam Energy Scan Program from the STAR collaboration.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Inclusive measurements at HERA from low to high x, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Behnke, Olaf
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: New inclusive Deep Inelastic Scattering (DIS) measurements are presented, obtained with the H1 and ZEUS detectors at HERA. The results...
Show moreNew inclusive Deep Inelastic Scattering (DIS) measurements are presented, obtained with the H1 and ZEUS detectors at HERA. The results comprise (flavour) inclusive DIS cross sections as well as inclusive charm production. In the area of inclusive DIS, both H1 and ZEUS completed last year their high Q2 Neutral and Charged current measurements exploiting the large statistics from the HERA II running period. For inclusive charm production, H1 and ZEUS published a combination of numerous existing measurements based on various tagging methods. Among other things a precise determination of the running charm quark mass mc(mc) was obtained from the combined data.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: ELIASHBERG ANALYSIS OF CUPRATE OXIDE SUPERCONDUCTORS
Creator: Ahmadi, Omid
Date: 2011-11, 2011-12
Description: In this thesis, evidence for antiferromagnetic spin uctuations as the pairing glue in high temperature superconductors is presented through a...
Show moreIn this thesis, evidence for antiferromagnetic spin uctuations as the pairing glue in high temperature superconductors is presented through a modi ed Eliashberg analysis of experimental tunneling data of Bi2212 over a wide range of doping. In particular, the normalized conductance data of the junctions, from optimal to overdoped, will be tted at T=0K using d-wave Eliashberg equations where the spectral function is modeled after spin uctuation spectra seen in experiments. The corresponding real and imaginary diagonal and anomalous self-energy curves are extracted and compare well to photoemission experiments. This is followed by a temperature dependent Eliashberg analysis where the spectral function is now temperature dependent, based on trends seen in inelastic neutron scattering experiments. New results for temperature dependent self energy curves are also compared to experiment with slight deviations. Finally, the Josephson product is calculated as an independent check of the tunneling matrix used in tting the data.
Ph.D. in Physics, December 2011
Show less

Title: Boosted heavy particles and jet substructure with the CMS detector, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Marchesini, Ivan
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: In the last years, the understanding of jets and jet substructure has become increasingly important, in particular in the context of new...
Show moreIn the last years, the understanding of jets and jet substructure has become increasingly important, in particular in the context of new physics searches. Many new physics models involve highly boosted hadronically-decaying particles, which result in jet-like objects with large masses and an intrinsic substructure. Discrimination of these heavy jets from ordinary quark and gluon jets is possible through a plethora of new techniques. The understanding of jets can be exploited also for the identification of pileup jets and for the discrimination between quark jets and gluon jets. A sampling of these techniques is discussed together with their validation on collider data recorded in proton-proton collisions at √s = 8TeV with the CMS detector in the year 2012. The commissioning in the boosted regime of algorithms used to identify jets originating from bottom quarks is also discussed. Many studies have highlighted the potential of using jet substructure techniques to improve the sensitivity in physics searches. An overview of recent CMS results employing these techniques is presented.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: High-order cumulants from the 3D O(1) and O(4) spin models, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Pan, Xue, Wu, Yuafang, Chen, X. S., Chen, Lizhu
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: We simulate the 3D O(1) (Ising) and O(4) spin models by the Monte Carlo method. Interesting high-order cumulants from the 3D Ising and O(4)...
Show moreWe simulate the 3D O(1) (Ising) and O(4) spin models by the Monte Carlo method. Interesting high-order cumulants from the 3D Ising and O(4) universality classes are presented and discussed. They all show the non-monotonic or sign change behavior. The critical behavior is instructive to that of the high-order cumulants of the net baryon number in the QCD phase transitions. Maybe it’s difficult to distinguish the universality classes by the high-order cumulants in the heavy ion collisions.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Influence of the target on multiparticle production in the forward domain in p+Pb collisions at 158 GeV, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Rybczyński, Maciej
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: In this talk we show the influence of the target on multiparticle production in the forward hemisphere in p+Pb collisions at top SPS energy....
Show moreIn this talk we show the influence of the target on multiparticle production in the forward hemisphere in p+Pb collisions at top SPS energy. The multiplicity distributions appear to be almost target independent in the projectile fragmentation domain and the effect of fluctuations of the number of target participants is not seen in the projectile fragmentation region. We compare the obtained results with those for p+p interactions and predictions of models.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: The potential importance of low luminosity and high energy at the LHC, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: White, Alan R.
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: Low luminosity runs at higher LHC energy could provide definitive evidence for an electroweak scale sextet quark sector of QCD that produces...
Show moreLow luminosity runs at higher LHC energy could provide definitive evidence for an electroweak scale sextet quark sector of QCD that produces electroweak symmetry breaking and dark matter within the bound-state S-Matrix of QUD - a massless, weak coupling, infra-red fixed-point, SU(5) field theory that might underly and unify the full Standard Model.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Minimum-bias angular and trigger-associated correlations from 200 GeV p-p collisions: jets, flows, centrality, and the underlying event, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Prindle, D.
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: The mechanisms leading to the hadronic final state of high-energy proton-proton collisions remain an unresolved issue at the RHIC and LHC. A...
Show moreThe mechanisms leading to the hadronic final state of high-energy proton-proton collisions remain an unresolved issue at the RHIC and LHC. A substantial contribution to the hadronic final state from minimum-bias (MB) jets is dominated by non-perturbative processes and may provide the common base for any high-energy dijet. Observation of a same-side (on azimuth)“ridge” in LHC p-p collisions suggests to some that hydrodynamic flows may play a role in that small system at higher energies. The issue of p-p centrality vs triggered jets has emerged in the context of gluon trans- verse distributions in the proton inferred from DIS data. Attempts have been made to isolate and study the underlying event (UE) complementary to triggered dijets, and it is suggested that multiple parton interactions may contribute to the UE. Reference [1] considered theoretical and experimental results for UE systematics and p-p centrality in the context of a two-component (soft+hard) model derived from single-particle pt spectrum nch systematics. The study concluded that there may be a substantial contribution to the UE from the triggered dijet and that p-p centrality is not controlled significantly by a jet trigger condition (if p-p centrality is relevant at all). Further study of two-particle correlations in p-p collisions was called for, particularly the nch dependence of MB correlations. We report a comprehensive study of MB (no pt cuts) angular correlations and trigger-associated (TA) yt correlations (transverse rapidity yt = ln[(mt + pt)/mπ]) from 200 GeV p-p collisions. Angular correlations are characterized by 2D model fits that accurately distinguish among proton dissociation structure (soft), jet-related structure (hard) and a nonjet azimuth quadrupole. All angular correlations are simply represented by a (2+1)-component model. The hard and quadrupole component scale simply with the soft-component multiplicity ns, clarifying the role of centrality and the eikonal model in p-p collisions. 2D TA correlations project to a marginal 1D trigger spectrum that can be simply predicted from pt spec- trum nch dependence. 2D TA distributions can then be processed to reveal MB jet fragment (hard component) systematics comparable to measured fragmentation functions. Hard-component azimuth dependence relative to the trigger relates to UE studies. From TA analysis we can establish the kinematic limits of jet fragment production in p-p collisions.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Particle production sources in heavy ion collisions at RHIC and LHC, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Wolschin, Georg
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: A nonequilibrium statistical relativistic diffusion model (RDM) with three sources is applied to the analysis of charged-hadron distributions...
Show moreA nonequilibrium statistical relativistic diffusion model (RDM) with three sources is applied to the analysis of charged-hadron distributions in Au–Au collisions at RHIC energies, in Pb–Pb collisions at the current LHC energy of 2.76 TeV, and in p–Pb at 5.02 TeV. The relative sizes of the particle production sources at RHIC and LHC energies are investigated in pseudorapidity space as functions of incident energy. The midrapidity source that arises mostly from gluon-gluon collisions becomes more important than the fragmentation sources as the energy increases from RHIC to LHC.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Study of pp interactions at high multiplicity at U-70, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Aleev, A., Avdeichikov, V., Balandin, V., Borzunov, Yu., Chencov, Yu., Dunin, V., Furmanec, N., Kekelidze, G., Kireev, V., Kokoulina, E., Ladygin, V., Myalkovsky, V., Nikitin, V., Peshehonov, V., Petukhov, Yu., Rufanov, I., Yukaev, A., Zhidkov, N., Basiladze, S., Bogdanova, G., Erofeeva, I., Grishin, N., Grishkevich, Ya., Karmanov, D., Kramarenko, V., Leflat, A., Merkin, M., Popov, V., Tihonova, L., Vishnevskaya, A., Volkov, V., Voronin, A., Zverev, E., Ardashev, E., Afonin, A., Golovkin, V., Golovnya, S., Gorokhov, S., Kholodenko, A., Kiryakov, A., Kurchaniniv, L., Lobanov, I., Lobanova, E., Mitrofanov, G., Petrov, V., Pleskach, A., Polkovnikov, M., Ronzhin, V., Ryadovikov, V., Senko, V., Soldatov, M., Shalanda, N., Tsyupa, Yu., Vorobiev, A., Yakimchuk, V., Zapolsky, V., Kutov, A.
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: The E190 Experiment is aimed at the search for collective phenomena in a quark-gluon system and a hadron system. It is carried out at U-70 in...
Show moreThe E190 Experiment is aimed at the search for collective phenomena in a quark-gluon system and a hadron system. It is carried out at U-70 in IHEP, Protvino. The evidence of Bose-Einstein condensation of pions has been confirmed with a twofold increasing of sampling at a level of 7 standard deviations. We study soft photon (smaller than 60 MeV) yield by using of an electromagnetic calorimeter with low energy threshold. In the gluon dominance model we explain multiparticle production by the active gluons. In this model the estimation of the contribution of charge exchange has been obtained.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: Proton structure from multiparticle contribution to elastic pp-scattering at 7 TeV, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Dremin, I. M.
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: The parton content of protons gets strong peripheral contribution at 1 fm from multiparticle dynamics as revealed by the overlap function in...
Show moreThe parton content of protons gets strong peripheral contribution at 1 fm from multiparticle dynamics as revealed by the overlap function in the unitarity condition for elastic pp-scattering at 7 TeV.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
Show less

Title: NEW TOOLS FOR JET ANALYSIS IN HIGH ENERGY COLLISIONS
Creator: Duffty, Daniel
Date: 2015, 2015-05
Description: Our understanding of the fundamental interactions of particles has come far in the last century, and is still pushing forward. As we build...
Show moreOur understanding of the fundamental interactions of particles has come far in the last century, and is still pushing forward. As we build ever more powerful machines to probe higher and higher energies, we will need to develop new tools to not only understand the new physics objects we are trying to detect, but even to understand the environment that we are searching in. We examine methods of identifying both boosted objects and low energy jets which will be shrouded in a sea of noise from other pasts of the detector. We display the power of boosted-b tagging in a simulated W' search. We also examine the effetc of pile up on low energy jet reconstructions. For this purpose we develop a new priority-based jet algorithm, "p-jets", to cluster the energy that belongs together, but ignore the rest.
Ph.D in Physics, May 2015
Show less

repository.iit

Search the repository

Pages

Pages

Enabled Filters

Refine Results

Type

Date

Academic status of creator

Department

Subject

Creator

Rights