Search results for "hadron"
showing 10 items of 3505 documents
First operational experience of HIE-ISOLDE
2016
The High Intensity and Energy ISOLDE project (HIE-ISOLDE)* is a major upgrade of the ISOLDE facility at CERN. The energy range of the post-accelerator will be extended from 2.85 MeV/u to 9.3 MeV/u for beams with A/q = 4.5 (and to 14.3 MeV/u for A/q = 2.5) once all the cryomodules of the superconducting accelerator are in place. The project has been divided into different phases, the first of which (phase 1a) finished in October 2015 after the hardware and beam commissioning were completed**. The physics campaign followed with the delivery of both radioactive and stable beams to two different experimental stations. The characteristics of the beams (energies, intensities, time structure and b…
Success and challenges of flow harmonic analysis in LHC collisions from large to small systems
2022
One of the primary goals of heavy-ion physics is to understand the transport properties of the quark-gluon-plasma (QGP) which comprises the tiniest constituents, quarks and gluons, that prevailed in the first few microseconds after the Big Bang. The present most challenging part of the research is pinning down the critical point of the QGP, where the shear viscosity over entropy ratio (η/s) is at its minimum and very close to the lowest value in nature 1/(4π). Significant advances based on flow harmonic analysis have been made up to date. However, there are still few remaining challenges in experiments and theory to constrain the temperature dependence of η/s and ζ/s of the QGP. In this tal…
New Constraints of QCD Matter from Bayesian Parameter Estimation with LHC Data
2022
New constraints of QCD matter from improved Bayesian parameter estimation with the latest LHC data
2022
Transport properties of the matter created in heavy-ion collisions, the quark-gluon plasma (QGP), contain essential information about quantum chromodynamics (QCD). In this talk, we present our latest study in inferring the transport properties of QGP by an improved Bayesian analysis using the CERN Large Hadron Collider Pb-Pb data. The uncertainties of the extracted properties are reduced by adding new observables sensitive to specific shear and bulk viscosity, reflecting mostly nonlinear hydrodynamic responses. The analysis also reveals that higher-order harmonic flows and their correlations have a higher sensitivity to the transport properties than other observables. This observation shows…
Searches for lepton number violation and resonances in K± → πμμ decays
2017
The NA48/2 experiment at CERN collected a large sample of charged kaon decays to final states with multiple charged particles in 2003–2004. A new upper limit on the rate of the lepton number violating decay K±→π∓μ±μ± is reported: B(K±→π∓μ±μ±)<8.6×10−11 at 90% CL. Searches for two-body resonances X in K±→πμμ decays (such as heavy neutral leptons N4 and inflatons χ ) are also presented. In the absence of signals, upper limits are set on the products of branching fractions B(K±→μ±N4)B(N4→πμ) and B(K±→π±X)B(X→μ+μ−) for ranges of assumed resonance masses and lifetimes. The limits are in the (10−11,10−9) range for resonance lifetimes below 100 ps.
STATUS OF STRANGENESS ELECTRO-PRODUCTION AT MAMI
2009
At the Institut für Kernphysik in Mainz, Germany, the microtron MAMI has been upgraded to 1.5 GeV electron beam energy and can now be used to study strange hadronic systems. The magnetic spectrometer KAOS from GSI was dismantled and re-installed in the spectrometer facility operated by the A1 collaboration. The spectrometer's primary purpose is to study strangeness electro-production. Its compact design and its capability to detect negative and positive charged particles simultaneously under forward scattering angles complements the existing spectrometers. In 2008, an important milestone has been reached by the successful measurement of kaon production off a liquid hydrogen target. The ide…
Dynamical Hadrons: Case Studies of Meson-Meson and Meson-Baryon Molecules and Triangle Singularities
2020
In this thesis we use various methods to study the interaction of hadrons. We focus on topics related to exotic hadrons, such as tetraquarks from meson-meson interaction, pentaquarks from meson-baryon, and also triangular singularities. We show how experimental data can be explained with our theoretical models, and make predictions that can be compared with future experiments. In chapter 1 we show our method to describe meson-meson interactions, known as chiral unitary approach, showing how the interaction of pseudoscalars generates the f0(500), f0(980) and a0(980), which appear in the two articles discussed in this chapter: that of the eta_c -> eta pi+ pi- decay, and that of the a0(980)-f0…
"Figure 2" of "Measurement of jet-medium interactions via direct photon-hadron correlations in Au$+$Au and $d$$+$Au collisions at $\sqrt{s_{_{NN}}}=2…
2021
Per-trigger yield of hadrons associated to direct photons in Au+Au collisions for direct photon $p_T$ 5-9 GeV/$c$, compared with p+p baseline, in various $\xi$ bins.
"Figure 5a" of "Measurement of jet-medium interactions via direct photon-hadron correlations in Au$+$Au and $d$$+$Au collisions at $\sqrt{s_{_{NN}}}=…
2021
$I_{AA}$ vs $\xi$ for direct photon $p_{T}^{\gamma}$ of 5-7 GeV/$c$, 7-9 GeV/$c$, and 9-12 GeV/$c$.
"Figure 3" of "Measurement of jet-medium interactions via direct photon-hadron correlations in Au$+$Au and $d$$+$Au collisions at $\sqrt{s_{_{NN}}}=2…
2021
Per-trigger yield of hadrons associated to direct photons in d+Au collisions for direct photon $p_T$ 7-9 GeV/$c$, compared with p+p baseline, in various $\xi$ bins.