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Experimental Particle Physics with the LHCb detector at Cern

English title Experimental Particle Physics with the LHCb detector at Cern
Applicant Straumann Ulrich
Number 146644
Funding scheme Project funding
Research institution Physik-Institut Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Particle Physics
Start/End 01.04.2013 - 31.03.2015
Approved amount 1'100'193.00
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Keywords (9)

CKM Matrix; LHC; LHCb; CP violation; pp collisions; B meson; b quark; new physics; Standard Model

Lay Summary (German)

Lead
Das LHCb Experiment wird am LHC des Cern in Genf durchgefuehrt. Es befasst sich unter anderem mit den Unterschieden zwischen Materie und Antimaterie.
Lay summary
Das LHCb Experiment stellt einer von 4 Detektoren dar, die am LHC Beschleuniger am Cern installiert sind. Es ermöglicht die Rekonstruktion und Vermessung von Teilchen, die zum Beispiel bei Zerfällen von sogenannten Beauty-Quarks entstehen.  Die Beauty-Quarks und Anti-Beauty-Quarks werden bei der Kollision der beiden Protonenstrahlen erzeugt und existieren nur ganz kurze Zeit, sodass sie nur etwa einen cm weit fliegen können. Aufgrund von Quantenfluktuationen können bei den Zerfallsprozessen  sehr schwere Teilchen auftreten. Durch das genaue Studium seltener Zerfälle der Beauty-Quarks suchen wir nach Anzeichen von bisher unbekannten Prozessen und neuer Teilchen, die unser physikalisches Weltbild wesentlich verändern könnten. Die Gruppe an der Universität Zürich ist neben 53 anderen Universitäten beim LHCb Experiment stark engagiert. Sie entwickelte, baute, und betreibt einen der zentralen Detektoren von LHCb. Doktoranden und PostDocs, die unter anderem von diesem Gesuch unterstützt werden, analysieren die gemessenen Daten und tragen so zu den wissenschaftlichen Publikationen des LHCb Experimentes bei, besonders im Bereich der Suche nach den Grenzen des Standardmodells.
Direct link to Lay Summary Last update: 26.03.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
LHCb Detector Performance
Aaji R. et al. (704 other authors) (2015), LHCb Detector Performance, in International Journal of Modern Physics, A30, 1530022.
Search for the lepton flavour violating decay τ−→μ−μ+μ−
Aaji R. et al. (704 other authors) (2015), Search for the lepton flavour violating decay τ−→μ−μ+μ−, in Journal of High Energy Physics, 2015(02), 121.
Measurement of the forward W boson cross-section in pp collisions at √s=7 TeV
Aaji R. et al. (700 other authors) (2014), Measurement of the forward W boson cross-section in pp collisions at √s=7 TeV, in Journal of High Energy Physics, 2014(12), 25.
Observation of associated production of a Z boson with a D meson in the forward region
Aaji R. et al. (675 other authors) (2014), Observation of associated production of a Z boson with a D meson in the forward region, in Journal of High Energy Physics, 2014(04), 091.
Observation of Z production in proton-lead collisions at LHCb
Aaji R. et al. (704 other authors) (2014), Observation of Z production in proton-lead collisions at LHCb, in Journal of High Energy Physics, 2014(08), 030.
The LHCb Silicon Tracker
Elsasser Ch. (2014), The LHCb Silicon Tracker, in Journal of Instrumentation, 9, C01009.
The LHCb Silicon Tracker—Performance & radiation damage
Elsasser Ch. (2014), The LHCb Silicon Tracker—Performance & radiation damage, in Nuclear Instruments and Methods , A730, 13-17.
Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−
Aaij R. et al. (632 other authors) (2013), Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−, in Journal of High Energy Physics, 2013(8), 131.
Measurement of form-factor independent observables in the decay B0→K∗0μ+μ−
Aaji R. et al. (656 other authors) (2013), Measurement of form-factor independent observables in the decay B0→K∗0μ+μ−, in Physical Review Letters, 111(19), 191801.
Measurement of the B0s→μ+μ− branching fraction and search for B0→μ+μ− decays at the LHCb experiment
Aaji R. et al. (654 other authors) (2013), Measurement of the B0s→μ+μ− branching fraction and search for B0→μ+μ− decays at the LHCb experiment, in Physical Review Letters, 111(10), 101805.
Rare Decays
Elsasser Ch. (2013), Rare Decays, in EPJ Web of Conferences, 60, 04003.
Searches for violation of lepton flavour and baryon number in tau lepton decays at LHCb
Aaij R. et al. (631 other authors) (2013), Searches for violation of lepton flavour and baryon number in tau lepton decays at LHCb, in Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 724(1-3), 36-45.
Study of forward Z + jet production in pp collisions at √ s = 7 TeV
Aaji R. et al. (680 other authors) (2013), Study of forward Z + jet production in pp collisions at √ s = 7 TeV, in Journal of High Energy Physics, 2014(1), 033.
LHCb Silicon Detectors: Operational Experience and Run I to Run II Transition
Elsasser Ch., LHCb Silicon Detectors: Operational Experience and Run I to Run II Transition, in Proceedings of Science, Vertex2014, 005.
Observation of the rare B0s --> µ+ µ- decay from the combined analysis of CMS and LHCb data
V. Khachatryan et al. (2829 other authors), Observation of the rare B0s --> µ+ µ- decay from the combined analysis of CMS and LHCb data, in submitted to Nature.
Vertexing and Tracking Software at LHCb
Bowen E., Vertexing and Tracking Software at LHCb, in Proceedings of Science, Vertex2014, 038.

Collaboration

Group / person Country
Types of collaboration
LHCb Kollaboration Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
he 2nd International Conference on the Initial Stages in High-Energy Nuclear Collisions Talk given at a conference Proton-Ion Physics with LHCb - Results and Prospects 03.12.2014 Napa, United States of America Elsasser Christian;
Kruger 2014: The International Workshop on Discovery Physics at the LHC Talk given at a conference LHCb results in proton-nucleus collisions at the LHC 01.12.2014 Skukuza, South Africa Müller Katharina;
Kruger 2014: The International Workshop on Discovery Physics at the LHC Talk given at a conference Central exclusive quarkonia production in the forward region at LHCb 01.12.2014 Skukuza, South Africa Müller Katharina;
6th International Workshop on Multiple Partonic Interactions at the LHC Talk given at a conference Associated Boson Production in the forward acceptance 03.11.2014 Krakau, Poland Bursche Albert Friethjof;
The 13th International Workshop on Tau Lepton Physics Talk given at a conference Lepton flavour violation in tau decays at LHCb 15.09.2014 Aachen, Germany Chrzaszcz Marcin;
VERTEX2014: The 23rd International Workshop on Vertex Detectors Talk given at a conference LHCb Silicon Detectors: Operational Experience and Run I to Run II Transition 15.09.2014 Macha Lake, Czech Republic Elsasser Christian;
VERTEX2014: The 23rd International Workshop on Vertex Detectors Talk given at a conference Vertexing and tracking software at LHCb 15.09.2014 Macha Lake, Czech Republic Bowen Espen Eie;
XIIth International Conference on Heavy Quarks and Leptons Talk given at a conference Rare B and charm decays at LHCb 25.08.2014 Mainz, Germany Chrzaszcz Marcin;
XIIth International Conference on Heavy Quarks and Leptons Talk given at a conference Lepton flavour and number violation measurements at LHCb 25.08.2014 Mainz, Germany Chrzaszcz Marcin;
20th Particles and Nuclei International Conference Talk given at a conference Measurements with electroweak bosons at LHCb 24.08.2014 Hamburg, Germany Müller Katharina;
20th Particles and Nuclei International Conference Talk given at a conference LHCb results in proton-nucleus collisions at the LHC 24.08.2014 Hamburg, Germany Müller Katharina;
Rencontres du Vietnam 2014: Physics at LHC and beyond Talk given at a conference The LHCb Upgrades 10.08.2014 Quy-nhon, Vietnam Steinkamp Olaf;
10th Rencontres du Vietnam - Flavour Physics Conference Talk given at a conference Electroweak penguin decays to leptons at LHCb 27.07.2014 Quy-nhon, Vietnam Tresch Marco;
Institutsseminar Individual talk Electroweak and central exclusive measurements in the forward region at LHCb 08.07.2014 Heidelberg, Germany Müller Katharina;
SPS Annual meeting 2014 Poster Measurements in Association with Electroweak Bosons at LHCb 30.06.2014 Fribourg, Switzerland Elsasser Christian;
SPS Annual meeting 2014 Talk given at a conference Performance of the LHCb Silicon Tracker during LHC Run I 30.06.2014 Fribourg, Switzerland Elsasser Christian;
Low-x workshop Talk given at a conference QCD and forward physics at LHCb 17.06.2014 Kyoto, Japan Bursche Albert Friethjof;
Large Hadron Collider Physics Conference Talk given at a conference Heavy Ion Physics at LHCb 02.06.2014 New York, United States of America Elsasser Christian;
26th Rencontres de Blois on Particle Physics and Cosmology Talk given at a conference QCD and electroweak measurements in the forward region at LHCb 18.05.2014 Blois, France Müller Katharina;
26th Rencontres de Blois on Particle Physics and Cosmology Talk given at a conference Searches for New Physics with LHCb 18.05.2014 Blois, France Chrzaszcz Marcin;
The top charm frontier at the LHCb Talk given at a conference New LHCb measurement: Z plus D meson cross section 02.01.2014 CERN (Genf), Switzerland Bursche Albert Friethjof;
MPI@LHC Talk given at a conference Measurements with electroweak gauge bosons at LHCb 02.12.2013 Antwerpen, Belgium Bursche Albert Friethjof;
CERN Seminar Individual talk Latest results on $Z$ boson production from LHCb 08.10.2013 CERN (Genf), Switzerland Anderson Jonathan;
13th Topical Seminar on Innovative Particle and Radiation Detectors Talk given at a conference The LHCb Silicon Tracker 07.10.2013 Siena, Italy Elsasser Christian;
16th Lomonosov Conference on Elementary Particle Physics Talk given at a conference LHCb overview talk 22.08.2013 Moskau, Russia Steinkamp Olaf;
DPF 13 Talk given at a conference Studies of the electroweak penguin transitions and radiative B decays at LHCb 13.08.2013 Santa Cruz, United States of America Bowen Espen Eie;
Collider Cross Talk Individual talk Latest results on Bs/Bd --> µ+µ- from CMS and LHCb 25.07.2013 CERN (Genf), Switzerland Elsasser Christian;
EPS Talk given at a conference Studies of the electroweak penguin transitions b --> s µ+µ- and b --> d µ+µ- at LHCb 17.07.2013 Stockholm, Sweden Serra Nicola;
2013 CHIPP Annual Plenary Meeting Talk given at a conference LHCb physics results 25.06.2013 Sursee, Switzerland Elsasser Christian;
Low-x workshop Talk given at a conference Results and prospects on central exclusive production at LHCb 30.05.2013 Rehovot/Eilat, Israel Müller Katharina;
Large Hadron Collider Physics Conference Talk given at a conference Rare decays 13.05.2013 Barcelona, Spain Elsasser Christian;
Phenomenology Symposium Talk given at a conference Rare decays at LHCb 06.05.2013 Pittsburgh, United States of America Tresch Marco;


Self-organised

Title Date Place
Scientific Programming with Python 19.01.2015 Zürich, Switzerland
Advanced Scientific Programming in Python 01.09.2013 Zürich, Switzerland

Communication with the public

Communication Title Media Place Year
Other activities Führungen am CERN Western Switzerland 2013

Associated projects

Number Title Start Funding scheme
141547 FORCE: Maintenance & Operation for the LHC Experiments 2012 01.04.2012 FORCE / CERN
159948 Experimental Particle Physics with the LHCb detector at Cern 01.04.2015 Project funding
141140 FORCE 2012: Operation and upgrade of the LHCb experiment 01.04.2012 FORCE / CERN
154218 FLARE 2014-2015: Operation and upgrade of the LHCb experiment 01.04.2014 FLARE
152784 High Precision CP Violation Physics at LHCb 01.04.2014 Project funding
135453 Experimental Particle Physics at the LHC 01.04.2011 Project funding
147467 FLARE 2013: Operation and upgrade of the LHCb experiment 01.04.2013 FLARE
159948 Experimental Particle Physics with the LHCb detector at Cern 01.04.2015 Project funding

Abstract

The LHCb experiment [1] was designed to perform precision easurements of CP violation and rare decays of heavy quarks at the LHC. By measuring numerous decay modes of b and c hadrons, it performs consistency checks of the Standard Model of particle physics and searches for signs of physics beyond the Standard Model. Both the LHC and the LHCb experiment are looking back to two very successful years of operation. LHCb is routinely operating at twice its design instantaneous luminosity. About 1 fb??1 of good-quality data were collected in 2011. More than 1.4 fb??1 have already been accumulated in 2012 and about 2.2 fb??1 are expected by the end of the year. The data taking eciency is high. In 2011, more than 90% of the luminosity delivered by the LHC were recorded with good quality. This number has further improved to above 95% in 2012. Based on the analysis of data collected in 2010 and 2011, a total of 67 papers has already been submitted to journals, several more are in the pipeline. World-best measurements were achieved in many of LHCb s key analyses. Most results are limited by statistical uncertainties and signi cant improvements are expected from analyses of the combined 2011 and 2012 datasets, which are currently underway. More details on the status and performance of the LHCb experiment are given in Sec. 2. The Zurich group plays an important role in several physics analyses as well as in the operation of the detector. We made a leading contribution towards the design and construction of the LHCb Silicon Tracker (ST) and in particular of the Tracker Turicensis (TT), a large surface silicon microstrip detector upstream of the LHCb dipole magnet. We remain responsible for the maintenance and operation of this detector as well as for the calibration and quality of the data it delivers. The status of the ST and our role in its operation are described in Sec. 3. The precise understanding of the spatial alignment of the detector and of track reconstruction e-ciencies are crucial prerequisites for exploiting the physics potential of the detector and minimizing systematic uncertainties on the physics results. Our group has made signi cant contributions to the determination of these quantities, which are summarized in Sec. 4. In physics analyses, we have established ourselves as leading players in searches for New Physics in very rare decays and in B decays mediated by electroweak penguins, as well as in measurements of electroweak boson production in the forward region. These analyses and our contributions to them are described in Sec. 5, 6 and 7. Thanks to upgrades to the high-level trigger computer farm, which were in part made possible through a special grant from the Swiss National Science Foundation in 2011, LHCb is able to store data to disk at more than twice the originally foreseen rate. This enables the experiment to significantly expand its physics potential, but also puts additional strain on resources for oine computing. Our contributions to oine computing are briely summarized in Sec. 8. Plans for an upgrade of the LHCb detector during the long LHC shutdown foreseen for the years 2018/2019 are taking shape and have been well received by the community and the relevant committees at CERN. Several new groups have recently joined the collaboration with the intention to contribute to the upgrade. Our plans for participation in the LHCb upgrade are described in 9. In addition to our contributions to the physics and the operation of the experiment, members of our group have also taken on leading positions within the collaboration. Ulrich Straumann served as chair of the LHCb collaboration board from 2008 till 2012, Olaf Steinkamp has been a member of the LHCb Speakers Bureau since the beginning of 2011 and is chairing it in 2012.
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