Reduction of the 
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 meson abundance in heavy ion collisions

Cho, Sungtae; Lee, Su Houng

doi:10.1103/physrevc.97.034908

Cited by 24 publications

(84 citation statements)

References 45 publications

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“…The scattering with defects, in particular, is expected to stronger influence the lifetime of excited states in contrast to the ground state, due to a smaller number of resonant final states for the later, necessary for elastic scattering. Similarly, spatial variations of the band gap due to dielectric disorder should also affect the resonance energy of the excited states by a larger degree due to reduced cancellation effects of the bandgap renormalization and binding energy [37], yielding an increasing inhomogeneous broadening with the quantum number n. Therefore, the small constant offset between the calculated intrinsic linewidth and the measured broadening of the 3s state of a few meV (Fig. 3 (c)) can be assigned to the presence of residual inhomogeneities potentially remaining in the hBN-encapsulated samples.…”

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confidence: 99%

Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

et al. 2019

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The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature. The width of excitonic peaks provides information about the radiative decay and phonon-assisted scattering channels limiting the lifetime of these quasi-particles. While linewidth studies so far have been limited to the exciton ground state, encapsulation with hBN has recently enabled quantitative measurements of the broadening of excited exciton resonances. Here, we present a joint experimenttheory study combining microscopic calculations with spectroscopic measurements on the intrinsic linewidth and lifetime of higher exciton states in hBN-encapsulated WSe2 monolayers. Surprisingly, despite the increased number of scattering channels, we find both in theory and experiment that the linewidth of higher excitonic states is similar or even smaller compared to the ground state. Our microscopic calculations ascribe this behavior to a reduced exciton-phonon scattering efficiency for higher excitons due to spatially extended orbital functions. Monolayer transition metal dichalcogenides (TMDs)show pronounced Coulomb phenomena [1][2][3][4][5][6][7], which in bulk materials become observable predominantly at very low temperatures. Electron-hole pairs in TMDs exhibit binding energies of up to 0.5 eV giving rise to a Rydberg-like series of exciton states below the free particle bandgap [8][9][10][11]. While the relative position of excitonic resonances in optical spectra presents a fingerprint of Coulomb correlations [12][13][14], their linewidth contains information about their coherence lifetime and the underlying many-particle scattering processes. Previous studies on exciton linewidths in TMDs [15][16][17][18] have revealed efficient scattering into dark intervalley excitons [19] and have demonstrated strain-induced modifications of exciton-phonon scattering channels [20]. However, these studies have been restricted to the 1s exciton ground state, since the higher order resonances were dominated by inhomogeneous broadening and were challenging to resolve and analyze at elevated temperatures. Furthermore, exciton-phonon scattering within the rich phase space of excited exciton states has not been theoretically investigated in TMDs yet. Recently, the encapsulation of TMD materials in the layered wide-bandgap insulator hexagonal boron nitride (hBN) has been shown to drastically reduce the inhomogeneous broadening of excitonic resonances [10,11] and thereby enables to access temperature-dependent broadening of higher excitonic states.In this work, we present a joint experiment-theory study on the homogeneous broadening of higher excitonic resonances and the underlying microscopic scattering mechanism for the exemplary case of hBN-encapsulated * samuel.brem@chalmers.se Figure 1. Schematic illustration of the exciton bandstructure and possible scattering mechanisms. Optically generated excitons at zero center-of-mass momentum can dec...

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Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

et al. 2019

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“…We shall make use of the evolution equation for the abundances of particles included in processes discussed above. The momentum-integrated evolution equation has the form [37][38][39][40][41] …”

Section: Time Evolution Of the J/ψ Abundancementioning

confidence: 99%

“…We will assume that π,ρ,K,K * ,D, and D * are in equilibrium. Therefore, the density n i (τ ) can be written as [37][38][39][40][41] …”

Section: Time Evolution Of the J/ψ Abundancementioning

confidence: 99%

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Update on J/ψ regeneration in a hadron gas

et al. 2018

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In heavy-ion collisions, after the quark-gluon plasma there is a hadronic gas phase. Using effective Lagrangians, we study the interactions of charmed mesons which lead to J /ψ production and absorption in this gas. We update and extend previous calculations introducing strange meson interactions and also including the interactions mediated by the recently measured exotic charmonium resonances Z(3900) and Z (4025). These resonances open new reaction channels for the J /ψ, which could potentially lead to changes in its multiplicity. We compute the J /ψ production cross section in processes such as D ( * ) (s) +D ( * ) → J /ψ + (π,ρ,K,K * ) and also the J /ψ absorption cross section in the corresponding inverse processes. Using the obtained cross sections as input to solve the appropriate rate equation, we conclude that the interactions in the hadron gas phase lead to a 20-24% reduction of the J /ψ abundance. Within the uncertainties of the calculation, this reduction is the same at the Relativistic Heavy Ion Collider and the large Hadron Collider.

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“…In addition to that, the Coulomb law adopts a nonconventional form, deviating from the reciprocal distance dependence due to the dielectric contrast between the material and its environment. [9][10][11][12][13] In the recent literature on the subject, these effects have been taken into account and the free carrier screening has been addressed theoretically using a variety of high-level many-particle calculations, [14][15][16][17][18][19][20] resulting in a number of accurate quantitative predictions and descriptions of the experimental findings. Nevertheless, it remains useful and instructive in this context to explicitly examine the applicability of the low-frequency screening approximation from basic analytical arguments and provide a transparent illustration of the underlying physics.…”

Section: Introductionmentioning

confidence: 99%

Breakdown of the Static Approximation for Free Carrier Screening of Excitons in Monolayer Semiconductors

Glazov

Chernikov

2018

Physica Status Solidi (b)

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The authors address the problem of free carrier screening of exciton states in two‐dimensional monolayer semiconductors. Basic theoretical considerations are presented concerning the applicability of the commonly used static approximation of the screening effect and the implications are discussed. The authors show that the low‐frequency models leads to a major overestimation of the free carrier response and are inadequate to describe the screening of strongly bound excitons in monolayer materials. The presented arguments are consistent with existing high‐level many‐body theories and transparently illustrate the underlying physics.

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Reduction of the K* meson abundance in heavy ion collisions

Cited by 24 publications

References 45 publications

Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

Update on J/ψ regeneration in a hadron gas

Breakdown of the Static Approximation for Free Carrier Screening of Excitons in Monolayer Semiconductors

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