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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 h c (1 P ), χ c 2 (2 P ), , and  η b (1 S ). In addition, the unexpected and still-fascinating X (3872) has been joined by more than a dozen other charmonium- and bottomonium-like “ XYZ ” 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 , , and 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 industrial-strength 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 hot- and 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.

A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities 5.5 < Q 2 < 80 GeV 2 and inelasticities 0.2 < y < 0.6 is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of 290 pb - 1 . Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of Q 2 . Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective Q 2 -interval are also determined. Previous results of inclusive jet cross sections in the range 150 < Q 2 < 15 , 000 GeV 2 are extended to low transverse jet momenta 5 < P T jet < 7 GeV . The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of Q 2 , the strong coupling constant α s ( M Z ) is determined in next-to-leading order.

The relationship between blood flow velocities in retrobulbar vessels and blood flow at the optic nerve in glaucoma patients was assessed in a prospective study. The Heidelberg retina flowmeter (HRF) was used to assess optic nerve head blood flow in 13 open-angle glaucoma patients. In the same patients, color Doppler imaging (CDI) measurements were obtained from the ophthalmic artery, the central retinal artery and the posterior ciliary arteries. Using data for one randomly selected eye per subject, correlations between HRF recordings and CDI measurements were evaluated by means of Spearman’s rank correlation factor. All three HRF parameters correlated with CDI measurements obtained from retrobulbar vessels. The most marked correlations were those of the HRF parameter ‘volume’ with the end-diastolic velocity in the ophthalmic artery and the medial posterior ciliary artery (R = 0.79, p = 0.0012 and R = 0.81, p = 0.0007, respectively), and the peak systolic velocity in the lateral posterior ciliary artery (R = 0.82, p = 0.0006). The present study suggests that glaucoma patients with altered blood flow in retrobulbar vessels are likely to show an alteration in optic nerve blood flow as measured with the HRF.

The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at s = 319 GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of 351 pb - 1 . Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet measurements in hadronic collisions; this paper presents the first application of grooming to DIS data. The analysis is carried out in the Breit frame, utilizing the novel Centauro jet clustering algorithm that is designed for DIS event topologies. Events are required to have squared momentum-transfer Q 2 > 150 GeV 2 and inelasticity 0.2 < y < 0.7 . We report measurements of the production cross section of groomed event 1-jettiness and groomed invariant mass for several choices of grooming parameter. Monte Carlo model calculations and analytic calculations based on Soft Collinear Effective Theory are compared to the measurements.

Exclusive photoproduction of ρ 0 ( 770 ) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction γ p → π + π - Y . Reactions where the proton stays intact ( m Y = m p ) are statistically separated from those where the proton dissociates to a low-mass hadronic system ( m p < m Y < 10 GeV ). The double-differential cross sections are measured as a function of the invariant mass m π π of the decay pions and the squared 4-momentum transfer t at the proton vertex. The measurements are presented in various bins of the photon–proton collision energy W γ p . The phase space restrictions are 0.5 ≤ m π π ≤ 2.2 GeV , | t | ≤ 1.5 GeV 2 , and 20 ≤ W γ p ≤ 80 GeV . Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the m π π dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the ρ 0 ( 770 ) meson mass and width at m ρ = 770.8 - 2.7 + 2.6 ( tot. ) MeV and Γ ρ = 151.3 - 3.6 + 2.7 ( tot. ) MeV , respectively. The model is used to extract the ρ 0 ( 770 ) contribution to the π + π - cross sections and measure it as a function of t and W γ p . In a Regge asymptotic limit in which one Regge trajectory α ( t ) dominates, the intercept α ( t = 0 ) = 1.0654 - 0.0067 + 0.0098 ( tot. ) and the slope α ′ ( t = 0 ) = 0.233 - 0.074 + 0.067 ( tot. ) GeV - 2 of the t dependence are extracted for the case m Y = m p .

The strong coupling constant α s is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic ep scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of α s ( m Z ) at the Z -boson mass m Z are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be α s ( m Z ) = 0.1157 ( 20 ) exp ( 29 ) th . Complementary, α s ( m Z ) is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value α s ( m Z ) = 0.1142 ( 28 ) tot obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.

In High Energy Physics (HEP), analysis metadata comes in many forms -- from theoretical cross-sections, to calibration corrections, to details about file processing. Correctly applying metadata is a crucial and often time-consuming step in an analysis, but designing analysis metadata systems has historically received little direct attention. Among other considerations, an ideal metadata tool should be easy to use by new analysers, should scale to large data volumes and diverse processing paradigms, and should enable future analysis reinterpretation. This document, which is the product of community discussions organised by the HEP Software Foundation, categorises types of metadata by scope and format and gives examples of current metadata solutions. Important design considerations for metadata systems, including sociological factors, analysis preservation efforts, and technical factors, are discussed. A list of best practices and technical requirements for future analysis metadata systems is presented. These best practices could guide the development of a future cross-experimental effort for analysis metadata tools.

Exclusive photoproduction of$${{\\rho ^0}} (770)$$ρ 0 ( 770 ) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction$$\\gamma p \\rightarrow \\pi ^{+}\\pi ^{-}Y$$γ p → π + π - Y . Reactions where the proton stays intact ($${{{m_Y}} {=}m_p}$$m Y = m p ) are statistically separated from those where the proton dissociates to a low-mass hadronic system ($$m_p{<}{{m_Y}} {<}10~{{\\text {GeV}}} $$m p < m Y < 10 GeV ). The double-differential cross sections are measured as a function of the invariant mass$$m_{\\pi \\pi }$$m π π of the decay pions and the squared 4-momentum transfer t at the proton vertex. The measurements are presented in various bins of the photon–proton collision energy$${{W_{\\gamma p}}} $$W γ p . The phase space restrictions are$$0.5\\le m_{\\pi \\pi } \\le 2.2~{{\\text {GeV}}} $$0.5 ≤ m π π ≤ 2.2 GeV ,$$\\vert t\\vert \\le 1.5~{{\\text {GeV}^2}} $$| t | ≤ 1.5 GeV 2 , and$$20 \\le W_{\\gamma p} \\le 80~{{\\text {GeV}}} $$20 ≤ W γ p ≤ 80 GeV . Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the$${m_{\\pi \\pi }}$$m π π dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the$${{\\rho ^0}} (770)$$ρ 0 ( 770 ) meson mass and width at$$m_\\rho = 770.8{}^{+2.6}_{-2.7}~({\\text {tot.}})~{{\\text {MeV}}} $$m ρ = 770.8 - 2.7 + 2.6 ( tot. ) MeV and$$\\Gamma _\\rho = 151.3 {}^{+2.7}_{-3.6}~({\\text {tot.}})~{{\\text {MeV}}} $$Γ ρ = 151.3 - 3.6 + 2.7 ( tot. ) MeV , respectively. The model is used to extract the$${{\\rho ^0}} (770)$$ρ 0 ( 770 ) contribution to the$$\\pi ^{+}\\pi ^{-}$$π + π - cross sections and measure it as a function of t and$${W_{\\gamma p}}$$W γ p . In a Regge asymptotic limit in which one Regge trajectory$$\\alpha (t)$$α ( t ) dominates, the intercept$$\\alpha (t{=}0) = 1.0654\\ {}^{+0.0098}_{-0.0067}~({\\text {tot.}})$$α ( t = 0 ) = 1.0654 - 0.0067 + 0.0098 ( tot. ) and the slope$$\\alpha ^\\prime (t{=}0) = 0.233 {}^{+0.067 }_{-0.074 }~({\\text {tot.}}) ~{{\\text {GeV}^{-2}}} $$α ′ ( t = 0 ) = 0.233 - 0.074 + 0.067 ( tot. ) GeV - 2 of the t dependence are extracted for the case$$m_Y{=}m_p$$m Y = m p .

Inclusive e(+/-)p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of root s = 319 GeV with a total integrated luminosity of 333.7 pb(-1) shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative four-momentum transfer squared, Q(2), between 60 and 50 000GeV(2), and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF(3)(gamma Z). A measurement of the neutral current parity violating structure function F-2(gamma Z) is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.

Exclusive photoproduction of [Formula omitted] mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction [Formula omitted]. Reactions where the proton stays intact ( [Formula omitted]) are statistically separated from those where the proton dissociates to a low-mass hadronic system ( [Formula omitted]). The double-differential cross sections are measured as a function of the invariant mass [Formula omitted] of the decay pions and the squared 4-momentum transfer t at the proton vertex. The measurements are presented in various bins of the photon-proton collision energy [Formula omitted]. The phase space restrictions are [Formula omitted], [Formula omitted], and [Formula omitted]. Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the [Formula omitted] dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the [Formula omitted] meson mass and width at [Formula omitted] and [Formula omitted], respectively. The model is used to extract the [Formula omitted] contribution to the [Formula omitted] cross sections and measure it as a function of t and [Formula omitted]. In a Regge asymptotic limit in which one Regge trajectory [Formula omitted] dominates, the intercept [Formula omitted] and the slope [Formula omitted] of the t dependence are extracted for the case [Formula omitted].