Review of results using heavy ion collisions at CMS

Ultrarelativistic heavy ion collisions at the laboratory provide a unique chance to study quantum chromodynamics (QCD) under extreme temperature (${\approx}150\,\mathrm{MeV}$) and density (${\approx}1\,\mathrm{GeV}/\mathrm{fm}^3$) conditions. Over the past decade, experimental results from LHC have shown further evidence for the formation of the quark-gluon plasma (QGP), a phase that is thought to permeate the early Universe and is formed in the high-density neutron-star cores. Various QCD predictions that model the behavior of the low-$x$ gluon nuclear density, a poorly explored region, are also tested. Since the photon flux per ion scales as the square of the emitting electric charge $Z^2$, cross sections of so far elusive photon-induced processes are extremely enhanced as compared to nucleon-nucleon collisions. Here, we review recent progress on CMS measurements of particle production with large transverse momentum or mass, photon-initiated processes, jet-induced medium response, and heavy quark production. These high-precision data, along with novel approaches, offer stringent constraints on initial state, QGP formation and transport parameters, and even parametrizations beyond the standard model.Comment: Presented at the Workshop of QCD and Forward Physics at the EIC, the LHC, and Cosmic Ray Physics in Guanajuato, Mexico, November 18-21 2019. Complete proceedings are available at https://doi.org/10.17161/1808.3072

Immobilization of gluten in spherical matrices of food-grade hydrogels

The aim of this paper is to produce spherical encapsulates of wheat gluten in a food-grade biopolymer for preparing sheared meat analogs, to prevent instant fibrilization of the gluten during a pre-mixing step. The hydrogel should release the gluten inside the Couette Cell, as a result of the higher temperature and shear in the process. Both sodium alginate and κ-carrageenan were used as encapsulants. Spherical particles of hydrogel-gluten mixtures were produced by means of a dripping method using an encapsulator. While the particle properties of κ-carrageenan surpassed those of alginate in terms of controlled release of the core, the particle production using the encapsulator was more complicated. With κ-carrageenan, a layer of oil on top of the cross-linking bath fluid, as well as through the outer orifice of a concentric nozzle were required to obtain a good sphericity of the particles. For the alginate particles the use of oil was not necessary. Gluten loadings of 7% w/w were achieved with 1.5% w/w alginate and with 2% w/w κ-carrageenan. The water content of the particles can be easily controlled by a subsequent partial drying step. A mixture of Soy Protein Isolate and particles was sheared in the Couette Cell. Controlled release of the gluten from the alginate particles was not achieved properly by temperature or shear. The controlled release of the gluten was achieved at the processing conditions only with κ-carrageenan. Some fibrilization was observed in the sheared product, but the macrostructure was not yet well developed. However, an optimization of the shearing process for the use of the particles may lead to an improved structure for the meat analogs. Practical applications: This paper investigated the effect of encapsulation in hydrogels on the fibrilization behavior of wheat gluten upon contact with water. A cheap and easily scalable dripping technique was used to create spherical particles in which the gluten did not fibrilize, although the coating material consists of ≥95% of water. Upon reaching the process conditions in the shearing device, the gluten is released and able to form fibers. The results show that hydrogels can mechanically protect the core and act as a delivery structure. The protective and carrier functions of the hydrogel can alternatively be used for cores like food additives (e.g., vitamins) or even to pharmaceutical ingredients, not only for the production of meat analogs, but also in other food applications

New physics searches with heavy-ion collisions at the CERN Large Hadron Collider

This document summarises proposed searches for new physics accessible in the heavy-ion mode at the CERN Large Hadron Collider (LHC), both through hadronic and ultraperipheral gamma gamma interactions, and that have a competitive or, even, unique discovery potential compared to standard proton-proton collision studies. Illustrative examples include searches for new particles-such as axion-like pseudoscalars, radions, magnetic monopoles, new long-lived particles, dark photons, and sexaquarks as dark matter candidates-as well as new interactions, such as nonlinear or non-commutative QED extensions. We argue that such interesting possibilities constitute a well-justified scientific motivation, complementing standard quark-gluon-plasma physics studies, to continue running with ions at the LHC after the Run-4, i.e. beyond 2030, including light and intermediate-mass ion species, accumulating nucleon-nucleon integrated luminosities in the accessible fb(-1) range per month.Peer reviewe