B physics at CDF - the Beauty of hadron collisions

The CDF experiment at the Tevatron p-pbar collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e+e- colliders. This provides an unique, rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in Bs mixing, and b-> s penguin decays.Comment: 6 pages, 5 figures. Write-up of the proceedings of the "Third Workshop on Theory, Phenomenology and Experiments in Heavy Flavour Physics" (Capri2010

A Novel in situ Trigger Combination Method

Searches for rare physics processes using particle detectors in high-luminosity colliding hadronic beam environments require the use of multi-level trigger systems to reject colossal background rates in real time. In analyses like the search for the Higgs boson, there is a need to maximize the signal acceptance by combining multiple different trigger chains when forming the offline data sample. In such statistically limited searches, datasets are often amassed over periods of several years, during which the trigger characteristics evolve and system performance can vary significantly. Reliable production cross-section measurements and upper limits must take into account a detailed understanding of the effective trigger inefficiency for every selected candidate event. We present as an example the complex situation of three trigger chains, based on missing energy and jet energy, that were combined in the context of the search for the Higgs (H) boson produced in association with a $W$ boson at the Collider Detector at Fermilab (CDF). We briefly review the existing techniques for combining triggers, namely the inclusion, division, and exclusion methods. We introduce and describe a novel fourth in situ method whereby, for each candidate event, only the trigger chain with the highest a priori probability of selecting the event is considered. We compare the inclusion and novel in situ methods for signal event yields in the CDF $WH$ search. This new combination method, by virtue of its scalability to large numbers of differing trigger chains and insensitivity to correlations between triggers, will benefit future long-running collider experiments, including those currently operating on the Large Hadron Collider.Comment: 17 pages, 2 figures, 6 tables, accepted by Nuclear Instruments and Methods in Physics Research

Stringy origin of Tevatron Wjj anomaly

The invariant mass distribution of dijets produced in association with W bosons, recently observed by the CDF Collaboration at Tevatron, reveals an excess in the dijet mass range 120-160 GeV/c^2, 3\sigma beyond Standard Model expectations. We show that such an excess is a generic feature of low mass string theory, due to the production and decay of a leptophobic Z', a singlet partner of SU(3) gluons coupled primarily to the U(1) baryon number. In this framework, U(1) and SU(3) appear as subgroups of U(3) associated with open strings ending on a stack of 3 D-branes. In addition, a minimal model contains two other stacks to accommodate the electro-weak SU(2) \in U(2) and the hypercharge U(1). Of the three U(1) gauge bosons, the two heavy Z' and Z" receive masses through the Green-Schwarz mechanism. For a given Z' mass, the model is quite constrained. Fine tuning three of its free parameters is just sufficient to simultaneously ensure: a small Z-Z' mixing in accord with the stringent LEP data on the $Z$ mass; very small (less than 1%) branching ratio into leptons; and a large hierarchy between Z" and Z' masses. The heavier neutral gauge boson Z" is within the reach of LHC.Comment: v1 8 pages revtex; v2 better fit to the data (Z" within LHC reach), references added; v3 to appear in PL

Recent QCD results from the Tevatron

Recent QCD related results from the CDF and the D0 experiments are presented based on proton anti-proton collision data at sqrt(s)=1.96 TeV, taken in Run II of the Fermilab Tevatron Collider. Measured observables include inclusive photon and diphoton production, vector boson plus jets production, event shape variables, and inclusive multijet production. The measurement results are compared to QCD theory calculations in different approximations. A determination of the strong coupling constant from jet data is presented.Comment: 12 pages with 14 figures, to appear in the proceedings of the "Ringberg Workshop: New Trends in HERA Physics 2011", Ringberg Castle, Germany, 25-28 September, 201

Standard model explanation of a CDF dijet excess in Wjj

We demonstrate the recent observation of a peak in the dijet invariant mass of the Wjj signal observed by the CDF Collaboration can be explained as the same upward fluctuation observed by CDF in single-top-quark production. In general, both t-channel and s-channel single-top-quark production produce kinematically induced peaks in the dijet spectrum. Since CDF used a Monte Carlo simulation to subtract the single-top backgrounds instead of data, a peak in the dijet spectrum is expected. The D0 Collaboration has a small upward fluctuation in their published t-channel data; and hence we predict they would see at most a small peak in the dijet invariant mass spectrum of Wjj if they follow the same procedure as CDF.Comment: 3 pg., 2 figs, revtex, minor clarifications, to appear in Phys. Rev.

Background dependence of dimuon asymmetry in pˉp\bar p p interactions at s=1.96\sqrt{s} = 1.96 TeV

The D0 Collaboration has reported an anomalous charge asymmetry in the production of same-sign muon pairs at the Fermilab Tevatron. The magnitude of this effect depends on the subtraction of several backgrounds, the most notable of which is due to kaons being misidentified as muons either through decays in flight or punch-through. The present authors suggested a check on such backgrounds consisting of a tight restriction on the muon impact parameter $b$, to confirm that this excess was indeed due to $B_{(s)}$ meson decays. The D0 Collaboration has performed a related check applying transverse impact parameter (IP) restrictions, whose implications are discussed. We study background asymmetry predictions for events involving two muons with IP bounds which are complementary to each other. These predictions may be used in future measurements of the net charge asymmetry from $B_{(s)}$ decays.Comment: To be published in Physics Letters

Measurements of the Production, Decay and Properties of the Top Quark: A Review

With the full Tevatron Run II and early LHC data samples, the opportunity for furthering our understanding of the properties of the top quark has never been more promising. Although the current knowledge of the top quark comes largely from Tevatron measurements, the experiments at the LHC are poised to probe top-quark production and decay in unprecedented regimes. Although no current top quark measurements conclusively contradict predictions from the standard model, the precision of most measurements remains statistically limited. Additionally, some measurements, most notably the forward-backward asymmetry in top quark pair production, show tantalizing hints of beyond-the-Standard-Model dynamics. The top quark sample is growing rapidly at the LHC, with initial results now public. This review examines the current status of top quark measurements in the particular light of searching for evidence of new physics, either through direct searches for beyond the standard model phenomena or indirectly via precise measurements of standard model top quark properties

NWF-prosessiin perustuvan vedenpuhdistuksen käyttäjäpotentiaalin kartoitus Suomessa

Opinnäytetyön aiheena oli kartoittaa potentiaalisia asiakkaita NWF-prosessiin perustuvalle vedensuodatuslaitteistolle. Toimeksiantajana toimi Ferroplan Oy, joka on tuonut markkinoille Natwat-nimisen vedensuodatusjärjestelmän, joka perustuu NWF-prosessiin. Kartoituksen avulla Ferroplan Oy tekee suunnitelman asiakasvierailuja varten kohdentaakseen laitteiston markkinoinnin tehokkaasti potentiaalisiin asiakkaisiin. Laitteiston hyviä puolia ovat muun muassa kompakti koko, kemikaalittomuus ja vähäinen huoltotarve kulumattomien osien ansiosta. Natwat-laitteistossa vesi puhdistetaan strippauksen, ilmastuksen ja erilaisten suodattimien avulla. Työhön kuului kunnallisiin talousvedenkäsittelylaitoksiin kohdistuva kysely, jonka perusteella saatiin selville kyseisen laitoksen potentiaalisuus Natwat-laitteistolle. Jos laitoksen tuottama vesi ei ole laadultaan tarpeeksi hyvää ja laatuongelmia tuottaa erityisesti rauta ja mangaani tai laitokselle on tulossa saneeraus, on laitos potentiaalinen asiakas. Laitteisto sopii myös jätevesien puhdistukseen, ja kartoitukseen valittiin elintarviketeollisuuden tuotannonjätevesistä kaikkein haastavimmat kohteet, joita oli huomattavasti vähemmän talousvedenkäsittelylaitoksiin verrattuna. Kohteita olivat teurastamot sekä kalan-, lihan- ja siipikarjantuotantolaitokset. Selvisi, että suurimmalla osalla kartoitukseen valituista talousvedenkäsittelylaitoksista ei esiintynyt ongelmia aiheuttavia laatuhäiriöitä. Noin neljäsosa kartoitukseen valituista oli potentiaalisia Natwat-laitteiston käyttäjiä, ja eniten ongelmia raakavedessä aiheuttavat rauta ja mangaani, jotka ovat yleisiä Suomen vesistöissä. Kyselyn perusteella useassa elintarviketeollisuudenyrityksessä tuotannonjätevesien puhdistamiseen käytetään useaa menetelmää ennen vesien johtamista kunnalliseen viemäriin. Pelkkä rasvanerotus on käytössä noin neljänneksellä, ja muutama laitos käsittelee jätevetensä täysin itsenäisesti, eikä johda niitä kunnalliseen viemäriin.The objective of the Bachelors thesis was to locate potential users in Finland for a water purification system which is based on NWF-process. The thesis was commissioned by Ferroplan Oy. Ferroplan Oy has brought to the market a water purification system called Natwat, which is based on the NWF-process and especially designed for the removal of iron and manganese. After locating all the potential users Ferroplan is able to efficiently market the Natwat-system. Good qualities of the system are for example a compact size, usage without chemicals and minor need of maintenance because there are no wearing parts. Water is purified in the system with stripping, aerating and with many filters. The thesis included a survey by telephone where material was collected from municipal household water plants. The main task of the survey was to find out whether a respondent was a potential user or not. If the water treatment plant produces water that does not meet the quality recommendations or there is a renovation planned, the plant is a potential user of the NWF-process. The purification system is also suitable for wastewater treatment and, therefore some food industry facilities were also included in the survey. Facilities with the most challenging wastewater from the production were chosen; including slaughterhouses, fish, meat and poultry production plants. The survey revealed that most of the drinking water treatment plants did not have any problems with the water. A quarter of the plants chosen for the survey are potential users of the Natwat-system, and it was found that iron and manganese are the main problems with the raw water in Finland. As a result of the survey, it was also discovered that in several food industry facilities wastewater from the production goes through several treatment processes before it is discharged into the municipal sewage system. A quarter of the facilities, however, only separate grease from the water and a few treat the wastewater themselves before discharging it into the environment