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Institution

Paul Scherrer Institute

FacilityVilligen, Switzerland
About: Paul Scherrer Institute is a facility organization based out in Villigen, Switzerland. It is known for research contribution in the topics: Neutron & Large Hadron Collider. The organization has 9248 authors who have published 23984 publications receiving 890129 citations. The organization is also known as: PSI.


Papers
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TL;DR: In this paper, the decay of the standard model Higgs boson into four leptons via a virtual $W$- or $Z$-boson pair is described by consistently employing complex mass parameters for the gauge bosons.
Abstract: The decay of the standard model Higgs boson into four leptons via a virtual $W$- or $Z$-boson pair is one of the most important decay modes in the Higgs-boson search at the Large Hadron Collider. We present the complete electroweak radiative corrections of $\mathcal{O}(\ensuremath{\alpha})$ to these processes, including improvements beyond $\mathcal{O}(\ensuremath{\alpha})$ originating from heavy-Higgs effects and final-state radiation. The intermediate $W$- and $Z$-boson resonances are described (without any expansion or on-shell approximation) by consistently employing complex mass parameters for the gauge bosons (complex-mass scheme). The corrections to partial decay widths typically amount to some percent and increase with growing Higgs mass ${M}_{H}$, reaching about 8% at ${M}_{H}\ensuremath{\sim}500\text{ }\text{ }\mathrm{GeV}$. For not too large Higgs masses (${M}_{H}\ensuremath{\lesssim}400\text{ }\text{ }\mathrm{GeV}$) the corrections to the partial decay widths can be reproduced within $\ensuremath{\lesssim}2%$ by simple approximations. For angular distributions the corrections are somewhat larger and distort the shapes. For invariant-mass distributions of fermion pairs they can reach several tens of percent depending on the treatment of photon radiation. The discussed corrections have been implemented in a Monte Carlo event generator called Prophecy4f.

295 citations

Journal ArticleDOI
W. Decking, S. Abeghyan, P. Abramian, A. Abramsky  +478 moreInstitutions (15)
TL;DR: The European XFEL as discussed by the authors is a hard X-ray free-electron laser (FEL) based on a highelectron-energy superconducting linear accelerator, which allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard Xray pulses.
Abstract: The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created.

295 citations

Journal ArticleDOI
TL;DR: The PILATUS hybrid pixel detector as discussed by the authors combines silicon sensors with CMOS processing chips by a 2D micro bump-bonding interconnection technology developed at the Paul Scherrer Institute.
Abstract: The hybrid pixel technology combines silicon sensors with CMOS-processing chips by a 2D micro bump-bonding interconnection technology developed at Paul Scherrer Institute [C. Broennimann, E.F. Eikenberry, B. Henrich, R. Horisberger, G. Huelsen, E. Pohl, B. Schmitt, C. Schulze-Briese, M. Suzuki, T. Tomizaki, H. Toyokawa, A. Wagner. J. Synchrotron Rad. 13 (2005) 120 [1] ; T. Rohe, C. Broennimann, F. Glaus, J. Gobrecht, S. Heising, M. Horisberger, R. Horisberger, H.C. Kaestl, J. Lehmann, S. Streuli, Nucl. Instr. and Meth. Phys. Res. A 565 (2006) 303 [2] ]. PILATUS hybrid pixel detectors like other instruments [X. Llopart, M. Campell, R. Dinapoli, D. San Segundo, E. Pernigotti. IEEE Trans. Nucl. Sci. 49 (2002) 2279 [3] ; N. Boudet, J.-F. Berar, L. Blanquart, P. Breugon, B. Caillot, J.-C. Clemens, I. Koudobine, P. Delpierre, C. Mouget, R. Potheau, I. Valin, Nucl. Instr. and Meth. Phys. Res. A 510 (2003) 41 [4] ] are operating in the so-called “single photon counting mode”: Every X-ray quantum is directly converted into an electrical signal and counted by the detector system. Several prototype detectors in various geometries were produced, tested and established at different synchrotron beamlines worldwide. We explain the technology and present some recent highlights from various fields of applications.

293 citations

Journal ArticleDOI
TL;DR: In this article, a hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopy) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber.
Abstract: . A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal ( f 44 ). m/z 44 is due mostly to the ion fragment CO 2 + for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "ϰ org " parameter, and f 44 was determined and is given by ϰ org = 2.2 × f 44 − 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f 44 is correlated with the photochemical age of an air mass.

293 citations


Authors

Showing all 9348 results

NameH-indexPapersCitations
Andrea Bocci1722402176461
Tobin J. Marks1591621111604
Wolfgang Wagner1562342123391
David D'Enterria1501592116210
Andreas Pfeiffer1491756131080
Christoph Grab1441359144174
Maurizio Pierini1431782104406
Alexander Belyaev1421895100796
Ajit Kumar Mohanty141112493062
Felicitas Pauss1411623104493
Chiara Mariotti141142698157
Luc Pape1411441130253
Rainer Wallny1411661105387
Roland Horisberger1391471100458
Emmanuelle Perez138155099016
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202363
2022199
20211,299
20201,442
20191,330
20181,298