High energy physics experiments rely heavily on the detailed detector simulation models in many tasks. Running these detailed models typically requires a notable amount of the computing time ...available to the experiments. In this work, we demonstrate a new approach to speed up the simulation of the Time Projection Chamber tracker of the MPD experiment at the NICA accelerator complex. Our method is based on a Generative Adversarial Network – a deep learning technique allowing for implicit estimation of the population distribution for a given set of objects. This approach lets us learn and then sample from the distribution of raw detector responses, conditioned on the parameters of the charged particle tracks. To evaluate the quality of the proposed model, we integrate a prototype into the MPD software stack and demonstrate that it produces high-quality events similar to the detailed simulator, with a speed-up of at least an order of magnitude. The prototype is trained on the responses from the inner part of the detector and, once expanded to the full detector, should be ready for use in physics tasks.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Light flavour hadrons are copiously produced in hadronic and heavy-ion interactions and bring a wealth of information about properties of the produced medium and reaction dynamics. Having different ...masses, quark content and lifetimes, light flavour hadrons do not only serve as general observables in the soft sector, but also play an important role as high transverse momentum probes and signatures of the onset of collectivity in high-multiplicity collisions of small and large systems. In this manuscript, we review the most recent ALICE results on the production of different light-flavour hadrons, including transverse momentum spectra, yields, nuclear modification factors and particle ratios in pp, p-Pb, Xe-Xe and Pb-Pb collisions at LHC energies.
Abstract
The short-lived resonances produced in heavy-ion collisions probe the existence and the properties of the late hadronic phase of the nucleus-nucleus interactions. Due to their short ...lifetimes, the resonance final state yields are sensitive to competing processes of rescattering of daughter particles and regeneration of surrounding hadrons in the dense hadronic phase. The resonances also carry information about strangeness production and hadronization mechanisms. We report the expected properties of the resonances produced in heavy-ion collisions at NICA energies as well as the results of feasibility studies for reconstruction of resonances in the MPD experiment.
A hot and dense matter called strongly interacting quark-gluon plasma (sQGP) is created in heavy ion collisions at RHIC energies. Detailed study of the properties of this new state of matter is a ...driving force of recent research at RHIC. In these proceedings we present most recent PHENIX results for system size and energy dependence of hadron and jet production at high transverse momentum in heavy ion collisions at RHIC. We also report latest results for direct photon production including soft direct photon yields and anisotropic flow.
•Toroidal flow was used to control the S-L interface shape in vertical Bridgman configuration.•The flow was driven by a disk-shaped rotating Submerged Heater/Baffle.•The flow below the rotating ...baffle, closely resembles the flow in Czochralski melts.•Convex interface was maintained at 45 rpm.•Detailed 3D CFD numerical simulations are in solid agreements with of the NaNO3 experiments.•Toroidal flow carries heat radially out bypassing slow conduction through the crystal.
Toroidal flow was used to control the shape of the solid-liquid interface, while growing NaNO3 crystals in vertical Bridgman configuration. The flow was driven by a disk-shaped rotating Submerged Heater/baffle (SH). The flow in the inner melt, below the rotating SH/baffle, closely resembles the flow in Czochralski melts. The experiments were conducted in a transparent furnace which allowed side view to the solid-liquid interface. Without baffle rotation, interface was concave. For zero growth rate, convex interface was obtained typically at 15 rpm. The degree of convexity increased with rotation rate. While growing NaNO3 at 3.5 mm/h and 5.5 mm/h, convex interface was maintained at 45 rpm.
Detailed 3D CFD numerical simulations are in solid agreement with the NaNO3 experiments. The rotating baffle process is particularly useful for growing crystals of low thermal conductivity because flow, generated by baffle rotation, carries heat radially out bypassing slow conduction through the crystal.
The recent advances in 3D-printed silicone (PDMS: polydimethylsiloxane) implants present prospects for personalized implants with highly accurate anatomical conformity. However, a potential adverse ...effect, such as granuloma formation due to immune reactions, still exists. One potential way to overcome this problem is to control the implant/host interface using immunomodulatory coatings. In this study, a new cytokine cocktail composed of interleukin-10 and prostaglandin-E2 was designed to decrease adverse immune reactions and promote tissue integration by fixing macrophages into M2 pro-healing phenotype for an extended period of time. In vitro, the cytokine cocktail maintained low levels of pro-inflammatory cytokine (TNF-α and IL-6) secretions and induced the secretion of IL-10 and the upregulation of multifunctional scavenging and sorting receptor stabilin-1, expressed by M2 macrophages. This cocktail was then loaded in a gelatine-based hydrogel to develop an immunomodulatory material that could be used as a coating for medical devices. The efficacy of this coating was demonstrated in an in vivo rat model during the reconstruction of a tracheal defect by 3D-printed silicone implants. The coating was stable on the silicone implants for over 2 weeks, and the controlled release of the cocktail components was achieved for at least 14 days. In vivo, only 33% of the animals with bare silicone implants survived, whereas 100% of the animals survived with the implant equipped with the immunomodulatory hydrogel. The presence of the hydrogel and the cytokine cocktail diminished the thickness of the inflammatory tissue, the intensity of both acute and chronic inflammation, the overall fibroblastic reaction, the presence of oedema and the formation of fibrinoid (assessed by histology) and led to a 100% survival rate. At the systemic level, the presence of immunomodulatory hydrogels significantly decreased pro-inflammatory cytokines such as TNF-α, IFN-γ, CXCL1 and MCP-1 levels at day 7 and significantly decreased IL-1α, IL-1β, CXCL1 and MCP-1 levels at day 21. The ability of this new immunomodulatory hydrogel to control the level of inflammation once applied to a 3D-printed silicone implant has been demonstrated. Such thin coatings can be applied to any implants or scaffolds used in tissue engineering to diminish the initial immune response, improve the integration and functionality of these materials and decrease potential complications related to their presence.
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Resonance production in ALICE Riabov, V G
Journal of physics. Conference series,
01/2017, Letnik:
798, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Short-lived hadronic resonances provide the means to study properties of the quark-gluon plasma and the hadronic phase produced in heavy-ion collisions at the LHC. In these proceedings we review the ...most recent ALICE results on resonance production in pp, p-Pb and Pb-Pb collisions at different energies.
Abstract
Detailed detector simulation models are vital for the successful operation of modern high-energy physics experiments. In most cases, running detailed models requires a significant amount of ...computing resources. It is desired to have approaches that are less resource-intensive. In this work, we demonstrate the applicability of Generative Adversarial Networks (GAN) as a basis for such fast-simulation models for the case of the Time Projection Chamber (TPC) at the MPD detector at the NICA accelerator complex. Our prototype GAN-based model of TPC works faster than the detailed simulation in an order of magnitude without any noticeable drop in the quality of the high-level reconstruction characteristics for the generated data. Approaches with direct and indirect quality metrics optimization are compared.
Abstract
Photons serve as valuable probes of the properties of the hot and dense nuclear matter created in collisions of heavy ions. Thermal photon spectra at RHIC and LHC energies indicate that the ...temperature of the produced medium far exceeds the temperature of the phase transition to the quark-gluon plasma in lattice QCD calculations. Measurements of thermal photon spectra in heavy ion collisions at lower energies at the future NICA collider may help to trace the transition from partonic to hadronic degrees of freedom. In this contribution, feasibility studies on thermal photon measurements using the photon conversion method in the future MPD experiment at NICA will be reviewed. In this work, a possibility to increase photon reconstruction efficiency with a dedicated conversion layer is presented and feasibility to probe the material budget of the experiment with converted photons is discussed.
Abstract
Thermal photons serve as valuable probes of the hot and dense medium produced in heavy ion collisions. The effective thermal photon temperature measured at RHIC and LHC energies far exceeds ...the temperature predicted for the phase space transition into the deconfined state of quarks and gluons, known as quark-gluon plasma (QGP). Direct photon measurements in heavy ion collisions at the future NICA collider may help to estimate the effective temperature of the produced medium at lower energies and trace the transition from QGP to the hadron gas state. In this contribution, we present feasibility studies on the thermal photon measurements in AuAu collisions using the photon conversion method in the MPD experiment at NICA.
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