Production of 
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 and 
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 in central Pb + Pb collisions at 
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Loosely-bound objects such as light nuclei are copiously produced in proton-proton and nuclear collisions at the Large Hadron Collider (LHC), despite the fact that typical energy scales in such collisions exceed the binding energy of the objects by orders of magnitude. In this review we summarise the experimental observations, put them into context of previous studies at lower energies, and discuss the underlying physics. Most of the data discussed here were taken by the ALICE Collaboration during LHC Run1, which started in 2009 and ended in 2013. Specifically we focus on the production of (anti-)nuclei and (anti-)hypernuclei. Also included are searches for exotic objects like the H-dibaryon, a possible uuddss hexaquark state, or also a possible bound state of a Λ hyperon and a neutron. Furthermore, the study of hyperon-nucleon and hyperonhyperon interactions through measurements of correlations are briefly discussed, especially in connection with the possible existence of loosely-bound states composed of these baryons. In addition, some results in the strange and charmed hadron sector are presented, to show the capabilities for future measurements on loosely-bound objects in this direction. Finally, perspectives are given for measurements in the currently ongoing Run2 period of the LHC and in the future LHC Run3.

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“…usually connected to the description of flow in heavy-ion collisions [119,120,121,122,123,124,125,126,127].…”

Section: Coalescence Modelmentioning

confidence: 99%

Loosely-bound objects produced in nuclear collisions at the LHC

2019

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“…At first glance it may seem surprising that light nuclei with binding energies of a few MeV are produced at all in such violent collisions [2]. A number of models provide explanations [3], two of them being particularly popular: thermal production [4][5][6][7] and coalescence [8][9][10][11][12][13][14][15][16][17]. The thermal model assumes perfect chemical equilibrium above the chemical freeze-out temperature T CFO and a sharp chemical freeze out of all hadrons at T CFO .…”

Section: Introductionmentioning

confidence: 99%

Microscopic study of deuteron production in PbPb collisions at s=2.76TeV via hydrodynamics and a hadronic afterburner

et al. 2019

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The deuteron yield in Pb+Pb collisions at √ s NN = 2.76 TeV is consistent with thermal production at a freeze out temperature of T = 155 MeV. The existence of deuterons with binding energy of 2.2 MeV at this temperature was described as "snowballs in hell" [P. Braun-Münzinger, B. Dönigus, and N. Löher, CERN Courier, August 2015]. We provide a microscopic explanation of this phenomenon, utilizing relativistic hydrodynamics and switching to a hadronic afterburner at the above-mentioned temperature of T = 155 MeV. The measured deuteron p T spectra and coalescence parameter B 2 (p T) are reproduced without free parameters, only by implementing experimentally known cross sections of deuteron reactions with hadrons, most importantly π d ↔ π np.

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“…At first glance it may seem surprising that light nuclei with binding energies of a few MeV are produced at all in such violent collisions [2]. A number of models provide explanations [3], two of them being particularly popular: thermal production [4][5][6][7][8] and coalescence [9][10][11][12][13][14][15][16][17][18]. The thermal model assumes perfect chemical equilibrium above the chemical freeze-out temperature T CF O and a sharp chemical freeze-out of all hadrons at T CF O .…”

Section: Introductionmentioning

confidence: 99%

Centrality Dependence of Deuteron Production in PbPb Collisions at 2.76 TeV via Hydrodynamics and Hadronic Afterburner

Oliinychenko

Pang

Elfner

et al. 2019

Hot Quarks 2018—Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions

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The deuteron binding energy is only 2.2 MeV. At the same time, its yield in Pb+Pb collisions at √ s NN =2.76 TeV corresponds to a thermal yield at the temperature around 155 MeV, which is too hot to keep deuterons bound. This puzzle is not completely resolved yet. In general, the mechanism of light nuclei production in ultra-high energy heavy ion collisions remains under debate. In a previous work [1] we suggest a microscopic explanation of the deuteron production in central ultra-relativistic Pb+Pb collisions, the main mechanism being π pn ↔ πd reactions in the hadronic phase of the collision. We use a state-of-the-art hybrid approach, combining relativistic hydrodynamics for the hot and dense stage and hadronic transport for a later, more dilute stage. Deuteron rescattering in the hadronic stage is implemented explicitly, using its experimentally measured vacuum cross-sections. In these proceedings we extend our previous work to non-central collisions, keeping exactly the same methodology and parameters. We find that our approach leads to a good description of the measured deuteron transverse momentum spectra at centralities up to 40%, and underestimates the amount of deuterons at low transverse momentum at higher centralities. Nevertheless, the coalescence parameter B 2 , measured by ALICE collaboration, is reproduced well in our approach even for peripheral collisions.

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Production of ΛΛ and Λn¯ in central Pb + Pb collisions at s

Cited by 11 publications

References 59 publications

Loosely-bound objects produced in nuclear collisions at the LHC

Loosely-bound objects produced in nuclear collisions at the LHC

Microscopic study of deuteron production in PbPb collisions at s=2.76TeV via hydrodynamics and a hadronic afterburner

Centrality Dependence of Deuteron Production in PbPb Collisions at 2.76 TeV via Hydrodynamics and Hadronic Afterburner

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