Multiplicity Dependence of the Jet Structures in pp Collisions at LHC Energies

We study the event multiplicity dependence of the jet structure in pp collisions. We present evidence for jet shape modification due to multi-parton interactions using PYTHIA and HIJING++ Monte Carlo (MC) event generators as an input to our analysis. We introduce a characteristic jet size measure which is independent of the choice of the simulation parameters, parton distribution functions, jet reconstruction algorithms and even of the presence or absence of multi-parton interactions. We also investigate heavy-flavor jets and show the sensitivity of the multiplicity-differential jet structure to flavor-dependent fragmentation.Comment: Presented at Hot Quarks 2018 -- Workshop for young scientists on the physics of ultrarelativistic nucleus-nucleus collisions, Texel, The Netherlands, September 7-14 2018. Submitted to MDPI Proceeding

Latest results on Upsilon production in heavy-ion collisions from the STAR experiment

We report on the latest measurements of the production of Upsilon mesons in heavy-ion collisions from the STAR experiment at RHIC. New measurements of the nuclear modification factors of the Upsilon(1S+2S+3S) and Upsilon(1S) states in U+U collisions at sqrt{s_{NN}}=193 GeV are presented as a function of the number of participants (N(part)) in the collisions. In addition, the suppression of Upsilon(1S) and Upsilon(2S+2S) is presented versus the quark-antiquark binding energy. Preliminary results on ϒ suppression in Au+Au collisions at sqrt{s_{NN}}=200 GeV, reconstructed via the dimuon channel, are also reported

The role of the underlying event in the charm-baryon enhancement observed in pp collisions at LHC energies

We study the enhanced production of $\Lambda_c$ charmed baryons relative to that of charmed $D^0$ mesons in proton-proton collisions at LHC energies. We simulated collision events with the enhanced color-reconnection model in PYTHIA 8 MC generator and propose measurements based on the comparative use of different event-activity classifiers to identify the source of the charmed-baryon enhancement. We demonstrate that in this enhanced color-reconnection scenario the excess production is primarily linked to the underlying event and not to the production of high-momentum jets

Event-activity dependent production of strange and non-strange charmed baryons in the enhanced color-reconnection scheme

We investigated the production of charmed baryons with different isospin and strangeness content, compared to both charmed $D^0$ mesons and to the $\Lambda_c^+$ baryon in proton--proton collisions at LHC energies. We used the PYTHIA 8 Monte Carlo event generator with color-reconnection beyond leading color approximation and proposed methods based on event-activity classifiers to probe the source of the charm baryon enhancement. We conclude that in the considered model class, the isospin of the charmed baryon state has a strong impact on the enhancement pattern. Using the observables we propose, upcoming high-precision experimental data will be able to differentiate between mechanisms of strangeness and charm enhancement

Correlation of Heavy and Light Flavors in Simulations

The ALICE experiment at the Large Hadron Collider (LHC) ring is designed to study the strongly interacting matter at extreme energy densities created in high-energy heavy-ion collisions. In this paper we investigate correlations of heavy and light flavors in simulations at LHC energies at mid-rapidity, with the primary purpose of proposing experimental applications of these methods. Our studies have shown that investigating the correlation images can aid the experimental separation of heavy quarks and help understanding the physics that create them. The shape of the correlation peaks can be used to separate the electrons stemming from b quarks. This could be a method of identification that, combined with identification in silicon vertex detectors, may provide much better sample purity for examining the secondary vertex shift. Based on a correlation picture it is also possible to distinguish between prompt and late contributions to D meson yields

Szingularitások vizsgálata és holomorf geometria = Study of singularities and holomorphic geometry

Szűcsnek és Lippnernek lényeges előrelépést sikerült elérni a szinguláris leképezések kobordizmuselméletének vizsgálatában. Chevalley, Weyl csoport invariáns polinomokról szóló tételének ekvivariáns (polinom, sima vagy valós-analitikus) leképezésekre vonatkozó analogonját bizonyitotta be (társszerzők segitségével) Szőke. Némethi több cikkében vizsgálta Heegaard Floer homológiák kiszámithatóságát, és jelentősen kiterjesztette Ozsváth és Szabó egy korábbi eredményét. Egy további munkában egy új homológia elméletet definiált (a rácshomológiát), mely talán a Heegaard Floer csoportokat is kiszámitja, és több szingularitáselméleti tétel alapjául is szolgált. Szingularitások csomóin pedig belátta hogy létezik egy kitüntetett kontakt struktúra, a Milnor betölthető. Stipsicz kontakt 3-sokaságokban élő Legendre és transzverz csomók invariánsait találta meg a megfelelő Heegaard Floer csoportokban. Ezen eszközök segitségével túlcsavart kontakt sokaságokban tudott csomókat vizsgálni. Szabóval és Parkkal pedig kis Euler karakterisztikájú 4-sokaságokon találtak egzotikus sima struktúrákat. Az utóbbi pár év kutatásaiból világossá vált, hogy a sutured Floer homológia a 3-sokaságok vizsgálatában nagyon fontos szerepet játszik, lehetővé téve csomók Seifert felületeinek megkülönböztetését és osztályozását, továbbá peremes 3-sokaságok komplexitásának mérését. Juhász ezen elméletnek mind megalkotásában, mind alkalmazásában döntő szerepet játszott. Vértesi Verának Heegaard Floer elméletbeli invariánsok segitségével sikerült végtelen sok nem transzverz egyszerű csomót mutatnia. | Szűcs managed to make an essential step forward in studying the cobordism theory of singular maps. In collaboration Szőke proved an equivariant analogue of Chevalley's theorem on Weyl group invariant polynomials for polynomial, smooth or real-analytic maps. In a number of articles Némethi examined computability of Heegaard Floer invariants, and exteded earlier results of Ozsváth and Szabó. In a further paper he defined a new homology theory, lattice homology, which might have close connection to Heegaard Floer theory, but already provided interesting results in the theory of surface singularities. He also showed that on the link of a surface singularity there is a distinguished contact structure, the Milnor fillable structure. Stipsicz (in collaboration with Ozsváth, Szabó and Lisca) have found a Heegaard Floer theoretic invariant of Legendrian and transverse knots which Can be fruitfully applied in studying, for example, knots in overtwisted contact structures. With Park and Szabó they showed exotic smooth structures on certain topological 4-manifolds with small Euler characteristic. Recent research has made it clear that sutured Floer homology plays an important role in the study of 3-manifolds, making it possible to distinguish and classify Seifert surfaces of knots; furthermore, to measure the complexity of 3-manifolds with boundary. Juhász played a crucial role both in developing and in applying the theory of sutured Floer homology. Using invariants from Heegaard Floer homology Vera Vértesi constructed infinitely many non transversaly simple knots

Nehézionfizikai és részecskefizikai kutatások a PHENIX/ RHIC és a TOTEM/LHC kísérletekben = Nuclear and particle physics research in PHENIX at RHIC and in TOTEM at LHC

2010 februárjában a PHENIX kísérlet együttműködésben publikáltuk a RHIC Au+Au ütközéseiben a direkt fotonok spektrumát. A RHIC Au+Au ütközéseiben már 2005-2007-ben feltárt tökéletes kvarkfolyadék 2010-es eredményünk szerint nem állhat hadronokból. Tehát kísérletileg igazoltuk a kvark-gluon plazma felfedezését a RHIC 200 GeV-es Au+Au ütközéseiben. A kvarkanyag a várakozásokkal ellentétben erősen csatoltnak bizonyult, szinte tökéletesen folyik, leírására a szokásos perturbatív eljárások nem alkalmazhatóak sikeresen. Kiemelkedő eredményünk volt az eta' mezon jelentős tömegmódosulásának felfedezése a RHIC gyorsító 200 GeV-es Au+Au ütközéseiben - ez a világon a leggyorsabban, 10**(-22) sec alatt bekövetkező, kísérletileg felfedezett tömegcsökkenés. Feltártuk a relativisztikus hidrodinamika új, egzakt és explicit megoldási osztályait, melyek segítségével megerősítettük és pontosítottuk a RHIC Au+Au ütközéseiben keletkező új anyag kezdeti hőmérsékletének és energiasűrűségének értékét és pontos értéket adtunk a közegbeli hangsebességre is. Új módszerünk alkalmazásával 2011-ben közöltük a CERN LEP L3 kísérletének adataiból készült filmfelvételünket, mely a világ legrövidebb ismert filmfelvétele lett, mivel a képsorozat 10**(-24) sec alatt véget ér. Lezártuk a TOTEM kísérlet építési szakaszát, és sikeresen publikáltuk a diffraktív p+p szórás differenciális hatáskeresztmetszetét az LHC sqrt(s) = 7 TeV-es energiáján. | In the PHENIX collaboration, the direct photon spectrum was measured in 200 GeV Au+Au collisions at RHIC. This 2010 paper proved, that the perfect fluid of quarks, found in the 2005-2007 period, cannot be explained in terms of hadrons because the initial temperature is larger than the Hagedorn limit. This result completes the proof of discovery of a quark-gluon plasma in 200 GeV Au+Au collisions. Surprizingly, this quark-matter is found to flow nearly perfectly and it cannot be successfully described using perturbative calculations. We reported a significant modification of the mass of the eta' meson in 200 GeV Au+Au collisions at RHIC. This is the fastest mass drop ever seen experimentally: it appears in less than 10**(-22) sec. We discovered new, explicit classes of exact solutions of relativistic hydrodynamics. We applied them to a precise determination of the initial temperature, the energy density and the speed of sound of the strongly interacting quark-gluon plasma in Au+Au collisions at RHIC. With our new method, we published a femtoscopic analysis of CERN LEP experiment L3 data. This study resulted in the fastest movie ever made by man: the sequence of pictures about this elementary particle reaction ends in less than 10**(-24) sec. We have completed the construction phase of the CERN LHC experiment TOTEM and we successfully published the differential cross-section in diffractive p+p collisions at sqrt(s) = 7 TeV energies

Activation of metrologically useful genuine multipartite entanglement

We consider quantum metrology with several copies of bipartite and multipartite quantum states. We characterize the metrological usefulness by determining how much the state outperforms separable states. We identify a large class of entangled states that become maximally useful for metrology in the limit of large number of copies, even if the state is weakly entangled and not even more useful than separable states. This way we activate metrologically useful genuine multipartite entanglement. Remarkably, not only that the maximally achievable metrological usefulness is attained exponentially fast in the number of copies, but it can be achieved by the measurement of few simple correlation observables. We also make general statements about the usefulness of a single copy of pure entangled states. We surprisingly find that the multiqubit states presented in Hyllus et al (2010 Phys. Rev. A 82 012337), which are not useful, become useful if we embed the qubits locally in qutrits. We discuss the relation of our scheme to error correction, and its possible use for quantum metrology in a noisy environment

Multicopy metrology with many-particle quantum states

We consider quantum metrology with several copies of bipartite and multipartite quantum states. We characterize the metrological usefulness by determining how much the state outperforms separable states. We identify a large class of entangled states that become maximally useful for metrology in the limit of infinite number of copies. The maximally achievable metrological usefulness is attained exponentially fast in the number of copies. We show that, on the other hand, pure entangled states with even a small amount of white noise do not become maximally useful even in the limit of infinite number of copies. We also make general statements about the usefulness of a single copy of pure entangled states. We show that the multiqubit states presented in Hyllus et al. [Phys. Rev. A 82, 012337 (2010)], which are not useful, become useful if we embed the qubits locally in qutrits. We discuss the relation of our scheme to error correction, and possible use for quantum information processing in a noisy environment.Comment: 7 pages including 3 figures + 5-page supplement including 2 figures, revtex4.