Measurement of the polar-angle distribution of leptons from W boson decay as a function of the W transverse momentum in proton-antiproton collisions at sqrt{s}=1.8 TeV

We present a measurement of the coefficient alpha_2 of the leptonic polar-angle distribution from W boson decays, as a function of the W transverse momentum. The measurement uses an 80+/-4 pb^{-1} sample of proton-antiproton collisions at sqrt{s}=1.8 TeV collected by the CDF detector and includes data from both the W->e+nu and W->mu+nu decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the Standard Model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c.Comment: 47 pages, 16 figures, submitted to Physical Review

Measurements of differential cross-sections in top-quark pair events with a high transverse momentum top quark and limits on beyond the Standard Model contributions to top-quark pair production with the ATLAS detector at √s = 13 TeV

Cross-section measurements of top-quark pair production where the hadronically decaying top quark has transverse momentum greater than 355 GeV and the other top quark decays into ℓνb are presented using 139 fb−1 of data collected by the ATLAS experiment during proton-proton collisions at the LHC. The fiducial cross-section at s = 13 TeV is measured to be σ = 1.267 ± 0.005 ± 0.053 pb, where the uncertainties reflect the limited number of data events and the systematic uncertainties, giving a total uncertainty of 4.2%. The cross-section is measured differentially as a function of variables characterising the tt¯ system and additional radiation in the events. The results are compared with various Monte Carlo generators, including comparisons where the generators are reweighted to match a parton-level calculation at next-to-next-to-leading order. The reweighting improves the agreement between data and theory. The measured distribution of the top-quark transverse momentum is used to search for new physics in the context of the effective field theory framework. No significant deviation from the Standard Model is observed and limits are set on the Wilson coefficients of the dimension-six operators OtG and Otq(8), where the limits on the latter are the most stringent to date. [Figure not available: see fulltext.]

Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector

This paper presents the measurement of the electroweak production of two jets in association with a $Z\gamma$ pair with the $Z$ boson decaying into two neutrinos. It also presents the search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector corresponding to an integrated luminosity of 139 fb$^{-1}$. The event signature, shared by all benchmark processes considered for measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. For electroweak production of $Z\gamma$ in association with two jets, the background-only hypothesis is rejected with an observed (expected) significance of 5.2 (5.1) standard deviations. The measured fiducial cross-section for this process is 1.31$\pm$0.29 fb. Observed (expected) upper limit of 0.37 (0.34) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson to a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017), assuming the 125 GeV Standard Model Higgs boson production cross-section

Nuorten päihteiden käyttö ja vanhempien saama tuki

Nuorten päihteiden käyttö on lisääntynyt viime vuosina. Nuoret eivät yleensä ole päihteistä riippuvaisia, mutta satunnainenkin kokeilu ja käyttö ovat haitallisia. Päihteiden käyttö voi olla yksittäinen ongelma, mutta myös osa suurempaa ongelmakokonaisuutta. Tämän vuoksi nuoren tilannetta tulee tarkastella kokonaisvaltaisesti. Päihteiden käyttöä ei aina huomata, ja sen ilmeneminen voi olla sokki läheisille. Päihteiden käyttö on ongelma käyttäjälle, mutta voi sairastuttaa myös läheiset. Läheiset, usein nuorten vanhemmat, tarvitsevat myös tukea ja neuvoa tilanteessa. Vanhempien oma asenne ja päihdekäyttäytyminen sekä nuoren asioista perillä oleminen ovat tärkeitä ehkäiseviä tekijöitä nuoren päihteiden käytölle. Myös nuoren oma asenne päihteisiin sekä sosiaaliset suhteet ja onnistumisen kokemukset ovat päihteiltä suojaavia tekijöitä. Tämä opinnäytetyö on tehty kokoamalla kattavasti teoriatietoa päihteistä, niiden käytöstä ja haitoista. Etelä-Karjalan sosiaali- ja terveyspiirin (Eksoten) internet-sivuilta selvitettiin, mistä ja miten voi hakea apua ja neuvoja läheisen päihteiden käytön ongelmiin. Lisäksi tehtiin kysely päihdenuorten vanhemmille. Kyselyllä selvitettiin päihdenuorten vanhempien omaa kokemusta saamastaan tuesta sosiaali- ja terveysalan ammattilaisilta. Tulokset analysoitiin empiirisesti. Tulosten mukaan osa vanhemmista on tyyty-väisiä saamaansa tukeen, osa taas kokee, ettei ole saanut tarpeeksi tukea ja tietoa. Päihdepalvelujen parempi ja määrällisesti laajempi saatavuus on kyse-lyyn vastanneiden vanhempien toiveissa. Tästä voidaan päätellä, että päih-denuorten vanhemmat otetaan huomioon ja tukea on tarjolla, mutta kaikkia tuki ei tavoita. Jatkotutkimuksessa voisi selvittää millaiseksi päihdenuoret kokevat saamansa hoidon. Lisäksi voisi selvittää miten sosiaali- ja terveysalan ammattilaiset koke-vat voivansa vaikuttaa nuorten päihdekäyttäytymiseen ja miten sosiaali- ja ter-veysalan ammattilaiset voisivat ottaa päihdenuorten vanhemmat paremmin huomioon. Kirjallisen nuorten päihdeasioita käsittelevän oppaan tekeminen ja jakaminen vanhemmille voisi olla hyödyllinen.Intoxicant use and abuse in young people has increased in recent years. Young people are generally not dependent on intoxicants, but occasional experimentation and use are harmful. Intoxicant use can be a single problem or part of a larger set of problems. Because of this, the situation of the young people should be considered from a broad perspective. Intoxicant use is not always noticed and its appearance may be a shock to those close to the user. Intoxicant use is a problem in the user, but can cause problems for families and friends, as well. Closely related, commonly parents, also need support and counsel in these situations. Parent's own attitudes and customs to use intoxicants, and knowing well issues about young people are important preventive factors for young people's intoxicant use. Also young people's attitude to intoxicant use and social affairs and experience of success are protective factors for intoxicant use. This thesis has been done by collecting comprehensive information on theory of intoxicant consumption and drawbacks of them. With the help of South Karelia District of Social and Health Service's websites, information about where and how to get help and advice for those close to young people with problems was found. In addition to this has been done an inquiry to parents of young people who use intoxicants. By the inquiry, the parents own experiences of having support from professionals in social and health care were examined. The results were analyzed empirically. According to the results, a proportion of parents are satisfied for support they have got, whereas part of parents find that they have not had enough support and information. The parents hope for better and wider availability of services for intoxicant users. Parents of young intoxicant abusers were taken into ac-count, and support services are available, but they do not reach all who need them. For further study, the opinions of the young people, and also of the health professionals about care of intoxicant abusers would be of interest

Using Fluorescence to Study Actomyosin in Yeasts

This year marks the 30th anniversary of the first description of the cellular distribution of actin within a yeast cell. Since then advances in both molecular genetics and imaging technologies have ensured research within these simple model organisms has blazed a trail in the field of actomyosin research. Many yeast proteins and their functions are functionally conserved in human cells. This, combined with experimental speed, minimal cost and ease of use make the yeasts extremely attractive model organisms for researching diverse cellular processes, including those involving actomyosin. In this chapter, current state-of-the-art fluorescence methodologies being applied to yeast actomyosin research, together with an honest appraisal of their limitations, such as the pitfalls that should be considered when fluorescently labelling proteins interacting within a dynamic cytoskeleton, will be described. Papers describing the established techniques developed for yeast localisation studies will be highlighted. This will provide the reader with an informed overview of the arsenal of imaging techniques available to the yeast actomyosin researcher and encourage them to consider novel ways these simple unicellular eukaryotes could be used to address their own research question

A search for t -> tau nu q in t(t)over-bar production

We present a search for t (t) over bar events with a tau lepton in the final state. The data sample corresponds to an integrated luminosity of 194 pb(-1) collected with the CDF II detector from p (p) over bar collisions at a center of mass energy of 1.96 TeV. We observe two events with an expected signal of 1.0 +/- 0.2 events and a background of 1.3 +/- 0.3 events. We determine a 95% confidence level upper limit on r(tau), the ratio of the measured rate of t -> tau nu q to the expectation, of 5.2

Inclusive double-Pomeron exchange at the Fermilab tevatron (p)over-barp collider

We report results from a study of events with a double-Pomeron exchange topology produced in (p) over barp collisions at roots=1800 GeV. The events are characterized by a leading antiproton and a large rapidity gap on the outgoing proton side. We find that the differential production cross section agrees in shape with predictions based on Regge theory and factorization, and that the ratio of double-Pomeron exchange to single diffractive production rates is relatively unsuppressed as compared to the O(10) suppression factor previously measured in single diffractive production

Measurement of the c-jet mistagging efficiency in tt¯ events using pp collision data at s√=13 TeV collected with the ATLAS detector

A technique is presented to measure the efficiency with which c-jets are mistagged as b-jets (mistagging efficiency) using tt¯ events, where one of the W bosons decays into an electron or muon and a neutrino and the other decays into a quark–antiquark pair. The measurement utilises the relatively large and known W→cs branching ratio, which allows a measurement to be made in an inclusive c-jet sample. The data sample used was collected by the ATLAS detector at s√=13 TeV and corresponds to an integrated luminosity of 139 fb−1. Events are reconstructed using a kinematic likelihood technique which selects the mapping between jets and tt¯ decay products that yields the highest likelihood value. The distribution of the b-tagging discriminant for jets from the hadronic W decays in data is compared with that in simulation to extract the mistagging efficiency as a function of jet transverse momentum. The total uncertainties are in the range 3–17%. The measurements generally agree with those in simulation but there are some differences in the region corresponding to the most stringent b-jet tagging requirement