| 1. |
- Aaron, F. D., et al.
(författare)
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Combined measurement and QCD analysis of the inclusive e(+/-)p scattering cross sections at HERA
- 2010
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :1
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Tidskriftsartikel (refereegranskat)abstract
- A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
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| 2. |
- Aaron, F. D., et al.
(författare)
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Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA
- 2010
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:3, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) > 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb.
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| 3. |
- Gimalieva, A. D., et al.
(författare)
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A survey of molecular line emission towards Herbig Be star V645 Cyg
- 2024
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Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 528:1, s. 108-121
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Tidskriftsartikel (refereegranskat)abstract
- We present a survey of molecular line emission towards the molecular cloud surrounding Herbig Be star V645 Cyg. The survey was performed with the 20-m Onsala space telescope at 3 and 4 mm. We detected emission lines of 33 molecules and their isotopologues from diatomic molecules to four COMs up to seven atoms. Using detected lines, we estimated molecular column densities and abundances relative to molecular hydrogen in local thermodynamic equilibrium (LTE) approximation for all molecules except for methanol, for which we obtained physical parameters using a non-LTE model. Moreover, in the basement of the non-LTE model of methanol line emission, we consider that there is a weak maser effect in the additional spectral component of 51–40 E methanol line at 84.521 GHz. We compared the molecular abundances with values found in several astrochemical templates: molecular clouds, hot cores, and photodissociation regions, and found that signatures of these different types can be found towards V645 Cyg. We also obtained maps of the cloud in several molecular emission lines. The peaks of CO and CH3OH emission are shifted from the direction of the star, but the CS, HCO+, HNC, HCN, and N2H+ emission peaks are observed directly towards the star. Exploring the gas kinematics around V645 Cyg, we found that velocity structure in the ambient molecular cloud on the scale ≈1.6–2.0 pc is not the same as within ≈0.5 pc found previously by other authors.
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| 4. |
- Kirsanova, M. S., et al.
(författare)
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Molecular gas in high-mass filament WB 673
- 2017
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Ingår i: Open Astronomy. - : Walter de Gruyter GmbH. - 2543-6376. ; 26:1, s. 99-105
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Tidskriftsartikel (refereegranskat)abstract
- We studied the distribution of dense gas in a filamentary molecular cloud containing several dense clumps. The center of the filament is given by the dense clump WB 673. The clumps are high-mass and intermediate-mass star-forming regions. We observed CS (2–1), 13 CO (1–0), C 18 O (1–0), and methanol lines at 96 GHz toward WB 673 with the Onsala Space Observatory 20-m telescope. We found CS (2–1) emission in the inter-clump medium so the clumps are physically connected and the whole cloud is indeed a filament. Its total mass is 10 4 M and mass-to-length ratio is 360 M pc 1 from 13 CO (1–0) data. Mass-to-length ratio for the dense gas is 3.4 34 M pc 1 from CS (2–1) data. The PV-diagram of the filament is V-shaped. We estimated physical conditions in the molecular gas using methanol lines. Location of the filament on the sky between extended shells suggests that it could be a good example to test theoretical models of formation of the filaments via multiple compression of interstellar gas by supersonic waves.
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