FPGA-Based Tracklet Approach to Level-1 Track Finding at CMS for the HL-LHC

During the High Luminosity LHC, the CMS detector will need charged particle tracking at the hardware trigger level to maintain a manageable trigger rate and achieve its physics goals. The tracklet approach is a track-finding algorithm based on a road-search algorithm that has been implemented on commercially available FPGA technology. The tracklet algorithm has achieved high performance in track-finding and completes tracking within 3.4 $\mu$s on a Xilinx Virtex-7 FPGA. An overview of the algorithm and its implementation on an FPGA is given, results are shown from a demonstrator test stand and system performance studies are presented.Comment: Submitted to proceedings of Connecting The Dots/Intelligent Trackers 2017, Orsay, Franc

Vain hintako ratkaisee? : Kestävän kehityksen huomioiminen julkisissa ateriahankinnoissa

Julkisilla ateriahankinnoilla on merkittävä asema suomalaisessa yhteiskunnassa. Julkisessa ruokahuollossa painotetaan erityisesti terveellisyyttä ja ravitsemusta. Julkisten ateriahankintojen kautta voidaan edistää terveellisiä ruokatottumuksia ja vähentää terveydenhuollon kustannuksia. Ruokailutottumuksilla voidaan vaikuttaa myös kestävään kehitykseen. Tutkimuksen tavoitteena oli selvittää kestävän kehityksen toteutumista julkisissa ateriahankinnoissa. Erityisesti huomiota kiinnitettiin kilpailutuksen toteutumiseen kestävän kehityksen näkökulmasta ja hinnan merkityksen analysointiin julkisissa ateriahankinnoissa. Sen lisäksi kartoitettiin informaation toimivuutta ruokahuollossa. Tämän tutkimuksessa käytetty aineisto perustuu loppukesällä 2008 tehtyyn kyselyyn, joka osoitettiin kuntien ruokapalveluista vastaaville henkilöille. Kysely lähetettiin kaikkiin Suomen kuntiin. Vastauksia saatiin 115 kunnasta, joten vastausprosentiksi muodostui 28. Vastauksista koottiin numeeriset perustiedot ja tuloksia tarkasteltiin prosentuaalisen jakauman perusteella. Kunnat jaoteltiin käyttämällä Tilastokeskuksen neljän kuntatyypin luokittelua: harvaan asuttu maaseutu, ydinmaaseutu, kaupunkien läheinen maaseutu ja kaupunki. Kuntatyyppivertailussa hyödynnettiin ei-parametrista varianssianalyysiä. Tutkimustulosten mukaan hinnalla oli keskeinen rooli julkisissa ateriahankinnoissa sekä kilpailutuskriteerinä että ateriapalvelujen suunnittelutyössä kaikissa kuntatyypeissä. Nykyajan palveluyhteiskunnassa tavoitellaan tehokkuutta ja taloudellisuutta, mikä on johtanut siihen, että myös julkisissa ateriahankinnoissa suositaan nopeasti ja helposti saatavia massatuotteita. Elintason nousun myötä ruoan saatavuus on lähes kaikille suomalaisille itsestään selvyys, mutta ruoan tuotanto ja sen alkuperä ovat jääneet kuluttajille etäisiksi. Tutkimustulokset osoittivat, että julkisten aterioiden taustoista kerrotaan kuluttajille varsin vähän, vaikka tämä olisi edullinen tapa nostaa julkisen ruokahuollon kestävyyttä

Measuring the Top Quark Pair Production Cross Section in ATLAS: A Cross Section Analysis on Stream Test Data Using b-Tagging

This thesis presents measurements of the top quark pair production cross section us- ing the ATLAS stream test data. The cross section is determined separately for the semileptonic mode, where events in the electron plus jets channel are isolated, and the dilepton mode, where events in the electron-muon channel are considered. The cross section is determined both with and without using tagging of b-quark jets. For the semileptonic mode, the measured cross section is σtt ̄ = 740 ± 57 pb without b-tagging and σtt ̄ = 788 ± 50 pb when using b-tagging. For the dilepton mode, the cross section is σtt ̄ = 655 ± 73 pb without b-tagging and σtt ̄ = 704 ± 86 pb when including b-tagging

Improper influence against prosecutors and judges in Finland and Sweden: Findings from two national surveys 2008

The web survey was carried out in 2008, targeting all prosecutors and judges in office in Finland and Sweden. The forms of improper influence addressed in the questionnaire were harassment, threats, violence, vandalism and corruption. The reference period applied was the preceding 18 months. The survey was carried out simultaneously in Finland and in Sweden using an identical questionnaire. Judges and prosecutors have experience of all of the listed forms of improper influences. However, the dominant forms of influence are harassment and threats. Victimisation occurred primarily at the workplace, and only rarely in the leisure time of the respondents. Most of the perpetrators were individuals who were not connected with criminal organisations. This is the case in particular when the victim was a judge. Occasionally, however, organised crime representatives were also observed to be involved. This was true for prosecutors in particular. Swedish prosecutors were harassed and threatened by organised crime representatives significantly more often than Finnish prosecutors. It was unusual that family members of the civil servants concerned were victimised, but also some such instances were reported, some of them quite serious. Again, such incidents were more likely in Sweden than in Finland. According to the respondents, the employer organisations of the respondents had not done very much to prevent such incidents or to protect their employees from improper influences. The respondents were also of the opinion that much more should be done about the problem. The respondents had many suggestions for improvements, some of them quite sophisticated. These included, inter alia, ideas concerning the way their work was organised, the protection of personal data, access control, and the physical design of the offices and courtrooms. Overall, the responses demonstrate that the persons involved should be consulted carefully when planning and implementing new measures to prevent improper influences and to minimize their impact

A high-performance track fitter for use in ultra-fast electronics

This article describes a new charged-particle track fitting algorithm designed for use in high-speed electronics applications such as hardware-based triggers in high-energy physics experiments. Following a novel technique designed for fast electronics, the positions of the hits on the detector are transformed before being passed to a linearized track parameter fit. This transformation results in fitted track parameters with a very linear dependence on the hit positions. The approach is demonstrated in a representative detector geometry based on the CMS detector at the Large Hadron Collider. The fit is implemented in FPGA chips and optimized for track fitting throughput and obtains excellent track parameter performance. Such an algorithm is potentially useful in any high-speed track-fitting application

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT