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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.

A bstract The cross section of the diffractive process e + p → e + Xp is measured at a centre-of-mass energy of 318 GeV, where the system X contains at least two jets and the leading final state proton p is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction with photon virtualities Q 2 < 2 GeV 2 and in deep-inelastic scattering with 4 GeV 2 < Q 2 < 80 GeV 2 . The results are compared to next- to-leading order QCD calculations based on diffractive parton distribution functions as extracted from measurements of inclusive cross sections in diffractive deep-inelastic scattering.

A bstract A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic ep scattering at HERA using data collected by the H1 experiment corresponding to an integrated luminosity of 290 pb −1 . The investigated phase space is spanned by the photon virtuality in the range of 4 < Q 2 < 100 GeV 2 and by the fractional proton longitudinal momentum loss x ℙ < 0 . 03. The resulting cross sections are compared with next-to-leading order QCD predictions based on diffractive parton distribution functions and the value of the strong coupling constant is extracted.

Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic e p scattering at HERA are presented as a function of the Feynman variable x F and of the centre-of-mass energy of the virtual photon-proton system W . The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 131 pb - 1 . The measurement is restricted to photons and neutrons in the pseudorapidity range η > 7.9 and covers the range of negative four momentum transfer squared at the positron vertex 6 < Q 2 < 100  GeV 2 , of inelasticity 0.05 < y < 0.6 and of 70 < W < 245 GeV. To test the Feynman scaling hypothesis the W dependence of the x F dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.

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.

IntroductionRecently, there is an increasing trend of using noninvasive tests to define coronary anatomy; the importance of physiology has been minimized. We report a case of angina treated based on the anatomic information, which was only cured after revascularization of the flow deficit related coronary artery identified by myocardial perfusion imaging. This case provides insight into the importance of the physiologic flow and the inability of coronary anatomy to determine flow impairment.CaseA 55-year-old obese male with a history of diabetes, hypertension, and dyslipidemia presented with complaints of chest discomfort and dyspnea on exertion. He was a long-time smoker. Myocardial perfusion imaging (MPI) showed 15% reversible defect involving the anteroapical and distal anterolateral segments of the left ventricle. Coronary angiography showed 80% stenosis in the midportion of the left circumflex (LCX) and equivocal proximal stenosis of the dominant right coronary artery (RCA). Intravascular ultrasonography (IVUS) of the RCA confirmed 62% area stenosis, and two stents were deployed with 0% residual stenosis. After 2 months, he presented with worsening of dyspnea. Repeat MPI showed 20% reversible defect of the lateral, anterolateral, inferolateral, and adjacent apices. Cardiac catheterization showed patent stents in the RCA and mid-80 to 90% stenosis of the nondominant LCX. The patient underwent cutting balloon coronary angioplasty of the LCX with 40% residual stenosis. Up to 3 years of follow-up, he has sustained relief in symptoms.DiscussionIn this case, initially, the decision of which coronary vessel to dilate was taken based on the anatomic information provided by IVUS assessment of coronary stenosis. Even though the dominant stenosed RCA was reopened successfully, the patient continued to have symptoms, which only improved after balloon angioplasty of the nondominant LCX. This case illustrates that the severity of anatomic stenosis does not determine the coronary flow reserve deficit.ConclusionConsidering coronary anatomic information now available noninvasively, such as with computed tomographic angiography, inappropriate coronary angioplasties, as in our case, may become an increasing occurrence. This can be avoided if the importance of physiologic flow measurement can be imparted to intervening cardiologists.

IntroductionThe Cabrol graft is a Dacron tube between the coronary arteries and the composite aortic graft in aortic root replacement. Very late presentation of myocardial ischemia related to the Cabrol conduit graft is exceedingly rare. Knowledge of this technique is vital for the accurate interpretation of the coronary angiograms and CT scan findings and crucial for the treatment planning in patients who have had previous implantation of the Cabrol graft.CaseA 44-year-old female with Marfan syndrome and aortic valve replacement 13 years prior presented to cardiology clinic with complaints of exertional chest pain and dyspnea. On examination, she had jugular venous distention, prosthetic metallic click, and peripheral edema. Myocardial perfusion imaging revealed 40% reversible defect involving the anterior, lateral, apical, and inferior segments of the left ventricle. Coronary angiography reported a dilated left main coronary artery originating from the right coronary cusp. However, CT scan of the chest demonstrated a single origin of the left main and right coronary arteries, with both measuring 8 mm. Old microfilm data documenting the surgical procedure were then obtained. The surgical procedure was a replacement of her aortic valve and ascending aorta, with the Cabrol interposition graft. With failure of medical management, the patient finally underwent left anterior descending artery bypass graft. At 4 and 12 months postoperatively, she remains angina free.DiscussionIn the Cabrol technique, a Dacron graft provides sound anastomosis and prevents pseudoaneurysm formation at coronary ostia. However, complications such as coronary Dacron graft occlusion via thrombosis, stenosis, or kinking caused by migration of the Cabrol limbs due to fibrosis can occur rarely. This case is unique as the ischemia was caused by surgical anatomic alteration, which has not been reported 13 years after the initial Cabrol procedure.ConclusionThis case illustrates the risk of misdiagnosis when performing and evaluating coronary angiography post-Cabrol procedure and allows a review of the differing mechanisms of coronary ischemia post-Cabrol grafting.

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 .

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.