No Arabic abstract
The Large Hadron Collider at CERN will open a new energy domain for heavy-ion physics. Besides ALICE, the dedicated heavy-ion experiment, also ATLAS and CMS are preparing rich physics programs with nucleus-nucleus collisions. Here we focus on open heavy-flavour and quarkonia studies, among the fields that will most benefit from the high centre-of-mass energy at the LHC. We discuss a few examples of physics issues that can be addressed and we present a selection and comparison (where possible) of results on the expected capability of the three experiments.
At LHC energy, heavy quarks will be abundantly produced and the design of the ALICE detector will allow us to study their production using several channels. The expected heavy-quark in-medium energy loss in nucleus-nucleus collisions at the LHC is calculated within a model, that is compared to the available heavy-quark quenching measurements at RHIC. The nuclear modification factors and heavy-to-light ratios of charm and beauty mesons are considered. The capability of the ALICE experiment for addressing this phenomenology is discussed.
Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-quark masses. The impact of these results on measurements at the LHC and elsewhere is also addressed.
Selected new results from the H1 and ZEUS collaborations on $ep$ interactions at 300 - 318 GeV centre-of-mass energy are presented. The full pre-upgrade integrated luminosity of HERA of 110 pb$^{-1}$ is used. Charm cross sections are measured up to high values of $x_B$ and $Q^2$ and are found to be well described by NLO QCD in the 3 flavour scheme. Orbitally excited $D$ mesons are observed; radial excitations are searched for, but are not seen. The first $b$ cross section measurement is confirmed with a lifetime based method, establishing the excess over NLO QCD.
Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select $b$- and $c$-quark jets is measured using data recorded by LHCb from proton-proton collisions at $sqrt{s}=7$ TeV in 2011 and at $sqrt{s}=8$ TeV in 2012. The efficiency for identifying a $b(c)$ jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum $p_{rm T} > 20$ GeV and pseudorapidity $2.2 < eta < 4.2$. The dependence of the performance on the $p_{rm T}$ and $eta$ of the jet is also measured.
We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.