708 research outputs found
Determination of Integrated Luminosity via W and Z Boson Production with the ATLAS Detector
The possibility to determine the recorded integrated luminosity via the
measurements of the W and Z boson production cross-sections with the ATLAS
detector is discussed. The current results based on 2010 data are briefly
summarized. Special attention is drawn to theoretical uncertainties of the
measurement. The latter give a large contribution to the systematic
uncertainties of the measurements. An outlook on the expected precision of an
analysis based on 1fb-1 is given and the implications on a possible luminosity
determination are discussed.Comment: presented at the LHC Lumi Days: LHC Workshop on LHC Luminosity
Calibration, 13-14 January 2011, CERN, Geneva, Switzerland;
CERN-Proceedings-2011-001, pp. 22-2
Review of single vector boson production in pp collisions at TeV
This review summarises the main results on the production of single vector
bosons in the Standard Model, both inclusively and in association with light
and heavy flavour jets, at the Large Hadron Collider in proton-proton
collisions at a center-of-mass energy of 7 TeV. The general purpose detectors
at this collider, ATLAS and CMS, each recorded an integrated luminosity of
and in the years 2010 and 2011,
respectively. The corresponding data offer the unique possibility to precisely
study the properties of the production of heavy vector bosons in a new energy
regime. The accurate understanding of the Standard Model is not only crucial
for searches of unknown particles and phenomena but also to test predictions of
perturbative Quantum-Chromo-Dynamics calculations and for precision
measurements of observables in the electroweak sector. Results from a variety
of measurements in which single W or Z bosons are identified are reviewed.
Special emphasis in this review is given to interpretations of the experimental
results in the context of state-of-the-art predictions.Comment: 60 pages, 64 figures, For Eur. Phys. J.
Diboson Production in Proton-Proton Collisions at TeV
This review article summarizes results on the production cross section
measurements of electroweak boson pairs (, , , and
) at the Large Hadron Collider (LHC) in collisions at a
center-of-mass energy of \TeV. The two general-purpose detectors
at the LHC, ATLAS and CMS, recorded an integrated luminosity of in
2011, which offered the possibility to study the properties of diboson
production to high precision. These measurements test predictions of the
Standard Model (SM) in a new energy regime and are crucial for the
understanding and the measurement of the SM Higgs boson and other new
particles. In this review, special emphasis is drawn on the combination of
results from both experiments and a common interpretation with respect to
state-of-the-art SM predictions.Comment: 60 page
Development and Performance of spark-resistant Micromegas Detectors
The Muon ATLAS MicroMegas Activity (MAMMA) focuses on the development and
testing of large-area muon detectors based on the bulk-Micromegas technology.
These detectors are candidates for the upgrade of the ATLAS Muon System in view
of the luminosity upgrade of Large Hadron Collider at CERN (sLHC). They will
combine trigger and precision measurement capability in a single device. A
novel protection scheme using resistive strips above the readout electrode has
been developed. The response and sparking properties of resistive Micromegas
detectors were successfully tested in a mixed (neutron and gamma) high
radiation field, in a X-ray test facility, in hadron beams, and in the ATLAS
cavern. Finally, we introduced a 2-dimensional readout structure in the
resistive Micromegas and studied the detector response with X-rays
From Lost Letters to Conditional E-Mail Responses: A Method to Assess Biased Behavior Online
This article introduces the Conditional E-mail Response Technique (CERT) as a systematic, hidden observation technique to measure behavioral tendencies. Although CERT derives from older techniques such as lost-letter/lost-e-mail techniques, we show how CERT is unique: each participant receives several e-mails with varying content, allowing the researcher to observe response rates and valence as a function of the manipulated content. Our study investigated discrimination against foreigners in the apartment rental market in Heidelberg (a German university city) by recording lessors' (non-) responses to 600 e-mails from fake applicants. Each owner (N = 120) received five applications for a one-room apartment via e-mail. Applicants' ethnic identities were communicated through their names. The results showed a remarkable bias against foreign names compared to German names. The response rates for foreign applicants were almost half that for German applicants (response rates were 78% for German names compared to 44-54% for American, Italian, Russian, and Turkish names). The relative risk of a rejecting response was up to eight times higher for e-mails appearing to come from foreigners. Applicants with foreign names were noticeably more likely to receive either no response or a negative response, that is, to have a negative outcome. There were also differences among the foreign applicant groups. We discuss the implications, ethical considerations, and advantages of CERT compared to other related techniques, as well as possible future uses
The Global Network of Cavities to Search for Gravitational Waves (GravNet): A novel scheme to hunt gravitational waves signatures from the early universe
The idea of searching for gravitational waves using cavities in strong
magnetic fields has recently received significant attention. Specifically,
discussions focus on cavities with relatively small volumes, which are
currently employed in the search for axions. In this context, we propose a
novel experimental scheme that enables the detection of gravitational waves in
the GHz regime, which could originate, for example, from primordial black hole
mergers. The scheme is based on synchronous measurements of cavity signals from
multiple devices operating in magnetic fields at distant locations. While
gravitational wave signatures might be detectable in individual cavities,
distinguishing them from noise is highly challenging. By analyzing the
correlation among signals from several, possibly geographically separated
cavities, it is not only possible to significantly enhance the signal-to-noise
ratio but also to investigate the source of those gravitational wave
signatures. In the context of this proposal, a first demonstration experiment
with one superconducting cavity is currently conducted, which is the basis of
the proposed data-analysis approaches. On this basis the prospects of GravNet
(Global Network of Cavities to Search for Gravitational Waves) are outlined in
the paper.Comment: 9 page
Searching for Gravitational Waves with CMS
The idea of searching for gravitational waves using cavities in strong
magnetic fields has recently received significant attention. Most concepts
foresee moderate magnetic fields in rather small volumes, similar to those
which are currently employed for axion-like particle searches. We propose to
use the magnet system of the Compact Muon Solenoid (CMS) experiment after the
high luminosity phase of the LHC as a key component for a future detector for
gravitational waves in the MHz frequency range. In this paper we briefly
discuss a possible cavity concept which can be integrated into CMS and
additionally provide a first estimation of its possible sensitivity.Comment: 4 pages, 2 figure
- …