Search

The TOTEM collaboration at the Large Hadron Collider, together with the D0 collaboration at the Tevatron collider at Fermilab, have announced the discovery of the odderon – a bound state of three gluons that was predicted about 50 years ago. The result was presented at CERN on March 5 and follows the joint submission in December 2020 of a CERN and Fermilab preprints by TOTEM and D0 reporting this observation. States comprising several gluons are usually called “glueballs”, and are peculiar objects made only of the carriers of the strong force. The advent of quantum chromodynamics led theorists to predict the existence of the odderon, C-odd gluonic compound. Proving its existence in high-energy collisions at Tevatron and LHC has been a major experimental challenge. The work is based on a model-independent analysis of data at medium-range momentum transfer. The TOTEM and D0 teams compared proton-proton data (recorded at collision energies of 2.76, 7, 8, and 13 TeV and extrapolated to 1.96 TeV), with Tevatron proton-antiproton data measured at 1.96 TeV. In agreement with theoretical predictions, the proton-proton cross-section exhibits a deeper dip and stays below the proton-antiproton cross-section until the bump region, thus evidence of odderon was found.

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, MW, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera–electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain MW ¼ 80;433:5 T 6:4stat T 6:9syst ¼ 80;433:5 T 9:4 MeV=c2, the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega–electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation. [ABSTRACT FROM AUTHOR]

At the end of December 2020, two collaborations: TOTEM (CERN) and D0 (Fermi National Laboratory, USA) published the results of joint studies which manifested the discovery of a bound state of gluons: odderon. The existence of this state was predicted based on quantum chromodynamics about 50 years ago, but for a long time, it was not possible to prove its existence experimentally. The discovery was made possible by comparing the differential cross-sections of proton-proton scattering with the cross-sections of the proton-antiproton scattering. The difference in cross-sections corresponds exactly to the theoretical calculations of the contribution of odderon to the scattering amplitude. Active role in the experiments at D0, and in general in search of glueballs during previous years, played our Kyiv group. The discovery is already considered one of the most important at CERN and Fermilab. [ABSTRACT FROM AUTHOR]

After an introduction motivating the study of quarkonium production, we review the recent developments in the phenomenology of quarkonium production in inclusive scatterings of hadrons and leptons. We naturally address data and predictions relevant for the LHC, the Tevatron, RHIC, HERA, LEP, B factories and EIC. An up-to-date discussion of the contributions from feed downs within the charmonium and bottomonium families as well as from b hadrons to charmonia is also provided. This contextualises an exhaustive overview of new observables such as the associated production along with a Standard Model boson (γ , W and Z), with another quarkonium, with another heavy quark as well as with light hadrons or jets. We address the relevance of these reactions in order to improve our understanding of the mechanisms underlying quarkonium production as well as the physics of multi-parton interactions, in particular the double parton scatterings. An outlook towards future studies and facilities concludes this review. [ABSTRACT FROM AUTHOR]

We present a review of the recent theoretical and experimental developments related to the field of diffraction, parton saturation, and forward physics. We first discuss our present understanding of the proton structure in terms of quarks and gluons, the degrees of freedom of quantum chromodynamics. We then focus on some of the main results on diffraction at the HERA electron–proton collider in DESY, Germany, at the Tevatron proton–antiproton collider at Fermilab, Batavia, US, and at the CERN Large Hadron Collider (LHC) proton–proton and nucleus–nucleus collider, which is located in Geneva, Switzerland. We also present a selected amount of results on diffraction and photon exchanges that can be done at the LHC experiments and at a future Electron Ion Collider (EIC) to be built in the US at Brookhaven National Laboratory, New York. [ABSTRACT FROM AUTHOR]

After a brief digression on the current landscape of theoretical physics and on some open questions pertaining to coherence with experimental results, still to be settled, it is shown that the properties of the deformed Minkowski space lead to a plurality of potential physical phenomena that should occur, provided that the resulting formalisms can be considered as useful models for the description of some aspects of physical reality. A list is given of available experimental evidence not easy to be interpreted, at present, by means of the more established models, such as the standard model with its variants aimed at overcoming its descriptive limits; this evidence could be useful to verify the predictions stemming from the properties of the deformed Minkowski space. The list includes anomalies in the double-slit-like experiments, nuclear metamorphosis, torsional antennas, as well as the physical effect of the “geometric vacuum” (as defined in analogy with quantum vacuum), in the absence of external electromagnetic field, when crossing critical thresholds of energy parameter values, energy density in space and energy density in time. Concrete opportunities are suggested for an experimental exploration of phenomena, either already performed but still lacking a widely accepted explanation, or conceivable in the application of the approach here presented, but not tackled until now. A tentative list is given with reference to experimental infrastructures already in operation, the performances of which can be expanded with limited additional resources.

The statistical event-by-event analysis of inelastic interactions of protons in emulsion at 800 GeV reveals the existence of group of events with Gaussian pseudorapidity distributions for produced particles, as suggested by hydrodynamic-tube model. Events belong to very central collisions of protons with heavy emulsion nuclei with probability of realization of less than 1% and with multiplicity of shower particles exceeding (2-3 times) the average multiplicity in proton-nucleus collisions in emulsion. Bjorken’s energy density for these events reaches 2.0 GeV per fm3. The data are interpreted as a result of the QCD phase transition in proton-tube collisions at Tevatron energies. [ABSTRACT FROM AUTHOR]

Recent measurements of top quark pair production cross-section, which is performed at the LHC and the Tevatron collider, are studied using Hessian profiling technique to obtain their impact on the parton distribution functions (PDFs). The top quark production data covers different center-of-mass energies s = 1. 9 6 , 5.02, 7, 8 and 13 TeV in either p p or p p ̄ collisions. It is explained how the Hessian profiling method may be used to assess the impact of these new data on PDFs and consequently on their predictions. In this research, the impact of recent measurements of top quark pair cross-sections on different CT14, MMHT2014 and NNPDF3.0 PDF sets is investigated. The analysis results show that the recent top quark production at the LHC and Tevatron data provide significant constraints in particular on the central value, relative uncertainties or both for the s -quark distribution and the gluon PDFs in both CT14 and MMHT2014 PDF sets and are insensitive to valence-quark PDFs. A small constraint on the ū -sea quark distribution for CT14 PDF is also observed. There is no impact on the NNPDF3.0 PDF set in presence of these data. [ABSTRACT FROM AUTHOR]

The Standard Model is a consistent and computable theory that successfully describes the elementary particle interactions. The strong, electromagnetic and weak interactions have been included in the theory exploiting the relation between group symmetries and group generators, in order to smartly introduce the force carriers. The group properties lead to constraints between boson masses and couplings. All the measurements performed at the LEP, Tevatron, LHC and other accelerators proved the consistency of the Standard Model. A key element of the theory is the Higgs field, which together with the spontaneous symmetry breaking, gives mass to the vector bosons and to the fermions. Unlike the case of vector bosons, the theory does not provide prediction for the Higgs boson mass. The LEP experiments, while providing very precise measurements of the Standard Model theory, searched for the evidence of the Higgs boson until the year 2000. The discovery of the top quark in 1994 by the Tevatron experiments and of the Higgs boson in 2012 by the LHC experiments were considered as the completion of the fundamental particles list of the Standard Model theory. Nevertheless the neutrino oscillations, the dark matter and the baryon asymmetry in the Universe evidence that we need a new extended model. In the Standard Model there are also some unattractive theoretical aspects like the divergent loop corrections to the Higgs boson mass and the very small Yukawa couplings needed to describe the neutrino masses. For all these reasons, the hunt of discrepancies between Standard Model and data is still going on with the aim to finally describe the new extended theory. [ABSTRACT FROM AUTHOR]

In this paper, the results of investigation of single and pair production of J / Ψ mesons in the D0 experiment at the Tevatron accelerator are considered. The contributions of single and double parton interactions to the total cross section of the pair production J / Ψ of mesons are estimated for the first time. With the help of these measurements, the effective cross section of double parton interactions σeff was calculated. [ABSTRACT FROM AUTHOR]

During the Tevatron data-taking period from April 2001 to September 2011 (Run-II), several searches for supersymmetric particles were performed. The results from searches by the CDF and DØ collaborations are concisely reviewed. This includes results up to the summer conferences of 2013. Model-independent and model-dependent limits on new particle production are set, and interpretations in supersymmetric models are given. Several limits from the Large Electron Positron (LEP) era have been extended. Specific results are placed into the context of the Tevatron performance expectations and a few of the current results from searches at the Large Hadron Collider (LHC).