Simulation study of χ c →J/Ψ+γ detection with J/Ψ→e + e − in pp collisions in the ALICE experiment at LHC

González, P.; Guevara, P. Ladrón de; Torres, E. López; Marı́n, A.; Serradilla, E.

doi:10.1140/epjc/s10052-009-0895-4

Cited by 14 publications

(21 citation statements)

References 7 publications

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“…Note that in a few works (e.g. [21,22]) a fairly different γ(z) = d ln f (z)/d ln Ω m (z) is taken, which coincides with Eq. (1) only when γ = const.…”

Section: Methodssupporting

confidence: 52%

Non-parametric reconstruction of growth index via Gaussian processes

Yin

Hao

2019

Sci. China Phys. Mech. Astron.

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The accelerated cosmic expansion could be due to dark energy within general relativity (GR), or modified gravity. It is of interest to differentiate between them, by using both the expansion history and the growth history. In the literature, it was proposed that the growth index γ is useful to distinguish these two scenarios. In this work, we consider the non-parametric reconstruction of the growth index γ as a function of redshift z from the latest observational data as of July 2018 via Gaussian Processes. We find that f (R) theories and dark energy models within GR (especially ΛCDM) are inconsistent with the results in the moderate redshift range far beyond 3σ confidence level. A modified gravity scenario different from f (R) theories is favored. However, these results can also be due to other non-trivial possibilities, in which dark energy models within GR (especially ΛCDM) and f (R) theories might still survive. In all cases, our results suggest that new physics is required.PACS numbers: 98.80.Es, 95.36.+x, 04.50.Kd

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“…Note that in a few works (e.g. [21,22]) a fairly different γ(z) = d ln f (z)/d ln Ω m (z) is taken, which coincides with Eq. (1) only when γ = const.…”

Section: Methodssupporting

confidence: 52%

Non-parametric reconstruction of growth index via Gaussian processes

Yin

Hao

2019

Sci. China Phys. Mech. Astron.

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“…Concerning χ c , a feasibility study has been performed on the detection of the radiative decay χ c → J/ψγ at midrapidity in pp collisions [1015]. The J/ψ has been reconstructed via its e + e − decay, while the photon conversion has been reconstructed from opposite-sign tracks with opening angle < 0.1 rad and mass < 0.175 GeV.…”

Section: Production Of χCj (1p ) and ψ(2s)mentioning

confidence: 99%

Heavy quarkonium: progress, puzzles, and opportunities

Brambilla¹,

Eidelman²,

Heltsley³

et al. 2011

Advances in the Physics of Particles and Nuclei

103

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A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the B-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau-Charm factories, JLab, the ILC, and beyond. The list of newly-found conventional states expanded to include hc(1P ), χc2(2P ), B + c , and η b (1S). In addition, the unexpected and still-fascinating X(3872) has been joined by * Editors † Section coordinators ‡ Corresponding author: bkh2@cornell.edu more than a dozen other charmonium-and bottomonium-like "XY Z" states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of cc, bb, and bc bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrialstrength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hotand cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.

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“…Since Ref. 16 first applied the GP method to investigate the dark energy, it has been widely used and has shown its powerful ability in cosmology [17][18][19][20][21][22][23][24][25][26] . The advantage of GP method is that it does not need the concrete form of the model, the only assumption is that the observational data points are drawn from the multivariate Gaussian distribution.…”

Section: Introductionmentioning

confidence: 99%

Non-parametric reconstruction of dark energy and cosmic expansion from the Pantheon compilation of type Ia supernovae *

Lin

Tang

2019

Chinese Phys. C

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The equation of state (EoS) of dark energy plays an important role in the evolution of the universe and arouses great interests in recent years. With the progress on observational technique, precise constraint on the EoS of dark energy becomes possible. In this paper, we reconstruct the EoS of dark energy and cosmic expansion using Gaussian processes (GP) from the most up-to-date Pantheon compilation of type Ia supernovae (SNe Ia), which consists of 1048 finely calibrated SNe Ia. The reconstructed EoS of dark energy has large uncertainty due to its dependence on the second order derivative of the construction. Adding the direct measurements of Hubble parameters H(z) as an additional constraint on the first order derivative can partially reduce the uncertainty, but is still not precise enough to distinguish between evolving and constant dark energy. Besides, the results heavily rely on the prior of Hubble constant H 0 . The H 0 value inferred from SNe+H(z) without prior is H 0 = 70.5 ± 0.5 km s −1 Mpc −1 . Moreover, the matter density Ω M has an unnegligible effect on the reconstruction of dark energy. Therefore, more accurate determinations on H 0 and Ω M are needed to tightly constrain the EoS of dark energy.

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Simulation study of χ c →J/Ψ+γ detection with J/Ψ→e + e − in pp collisions in the ALICE experiment at LHC

Cited by 14 publications

References 7 publications

Non-parametric reconstruction of growth index via Gaussian processes

Non-parametric reconstruction of growth index via Gaussian processes

Heavy quarkonium: progress, puzzles, and opportunities

Non-parametric reconstruction of dark energy and cosmic expansion from the Pantheon compilation of type Ia supernovae *

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