3,516 research outputs found
Present Limits on the Precision of SM Predictions for Jet Energies
We investigate the impact of theoretical uncertainties on the accuracy of
measurements involving hadronic jets. The analysis is performed using events
with a Z boson and a single jet observed in collisions at
= 1.96 TeV in 4.6 of data from the Collider Detector at
Fermilab (CDF). The transverse momenta (\pt) of the jet and the boson should
balance each other due to momentum conservation in the plane transverse to the
direction of the and beams. We evaluate the dependence of the
measured \pt-balance on theoretical uncertainties associated with initial and
final state radiation, choice of renormalization and factorization scales,
parton distribution functions, jet-parton matching, calculations of matrix
elements, and parton showering. We find that the uncertainty caused by parton
showering at large angles is the largest amongst the listed uncertainties. The
proposed method can be re-applied at the LHC experiments to investigate and
evaluate the uncertainties on the predicted jet energies. The distributions
produced at the CDF environment are intended for comparison to those from
modern event generators and new tunes of parton showering.Comment: Submitted to Nucl. Instr. and Meth.
Learning anatomy in the university of Oulu:influential factors to success during 2010â2017
Abstract. Learning anatomy in the University of Oulu: Influential factors to success during 2010â2017. Our research covers population of 1398 students from eight different medical and dental courses. We collected exam results from 21 anatomic and 14 histologic practical works and combined them with studentsâ background information received from the student register of our medical and dental faculties. The background information included studentsâ name, gender, year of birth, hometown, starting year of medical/dental studies, programme and previous degrees. This research was performed in priority to find possible connections and correlations between the practical work results and the background data. The main purpose was to see if the increasing group sizes have affected on academic performance.
We executed statistical analysis by using nonparametric tests Mann-Whitney U-test and Kruskal-Willisâ test for the distributional analysis and for the correlations we used Spearmanâs correlation coefficient while our result data was not normally distributed (tested with Kolmogorov-Smirnov). The program we used was IBM SPSS Statistics 22.
We found no correlation between the annual student population and the practical work exam results so the increasing group sizes has not affected on academic performance. A good performance in the histologic practical works correlated significantly with similar performance in the anatomic practical works (Ï = 0.409, p <0.001). Female students managed better in the histologic practical works (Ï = 0.103, p < 0.001) but in anatomic practical works there was statistically significant difference between genders. The dentistry students performed inferiorly compared to medical students: histology (Ï = -0.194, p < 0.001) and anatomy (Ï = -0.193, p < 0.001). According to our research the students who are 25â30 years old females studying medicine are going to have the strongest academic performance (histology: Ï = 0.232, p = 0.009; anatomy: Ï = 0.236, p = 0.008) in the anatomy course while the male students of dentistry are receiving the worst results
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
Prompt Decays of General Neutralino NLSPs at the Tevatron
Recent theoretical developments have shown that gauge mediation has a much
larger parameter space of possible spectra and mixings than previously
considered. Motivated by this, we explore the collider phenomenology of gauge
mediation models where a general neutralino is the lightest MSSM superpartner
(the NLSP), focusing on the potential reach from existing and future Tevatron
searches. Promptly decaying general neutralino NLSPs can give rise to final
states involving missing energy plus photons, Zs, Ws and/or Higgses. We survey
the final states and determine those where the Tevatron should have the most
sensitivity. We then estimate the reach of existing Tevatron searches in these
final states and discuss new searches (or optimizations of existing ones) that
should improve the reach. Finally we comment on the potential for discovery at
the LHC.Comment: 41 pages, minor changes, added refs and discussion of previous
literatur
Matching Tree-Level Matrix Elements with Interleaved Showers
We present an implementation of the so-called CKKW-L merging scheme for
combining multi-jet tree-level matrix elements with parton showers. The
implementation uses the transverse-momentum-ordered shower with interleaved
multiple interactions as implemented in PYTHIA8. We validate our procedure
using e+e--annihilation into jets and vector boson production in hadronic
collisions, with special attention to details in the algorithm which are
formally sub-leading in character, but may have visible effects in some
observables. We find substantial merging scale dependencies induced by the
enforced rapidity ordering in the default PYTHIA8 shower. If this rapidity
ordering is removed the merging scale dependence is almost negligible. We then
also find that the shower does a surprisingly good job of describing the
hardness of multi-jet events, as long as the hardest couple of jets are given
by the matrix elements. The effects of using interleaved multiple interactions
as compared to more simplistic ways of adding underlying-event effects in
vector boson production are shown to be negligible except in a few sensitive
observables. To illustrate the generality of our implementation, we also give
some example results from di-boson production and pure QCD jet production in
hadronic collisions.Comment: 44 pages, 23 figures, as published in JHEP, including all changes
recommended by the refere
National Populist Challenges to Europeâs Center Right: Three Questions for Europe
This paper analyses the National Populist Challenges to Europeâs Center Right. It assesses the cases of the UK, Germany and France. It poses three questions for Europe: How will political integration be achieved and maintained? What policies will foster economic inclusion in the Eurozone? And, third, what are the best means to achieve economic solvency and growth. The paper make a case that neoliberal economic policies over the past decades have undermined some nations' public sector and have also contributed to tensions between the geographical east and west of Europe
Phenomenology of the Heavy Flavored spin 3/2 Baryons in Light Cone QCD
Motivated by the results of the recent experimental discoveries for charm and
bottom baryons, the masses and magnetic moments of the heavy baryons with
containing a single heavy quark are studied within light cone QCD
sum rules method. Our results on the masses of heavy baryons are in good
agreement with predictions of other approaches, as well as with the existing
experimental data.Comment: 12 Pages, 18 Figures and 3 Tables. Based on: arXiv:0807.3481v2
[hep-ph](Nucl.Phys.B808:137-154,2009). To be Published in the Proceeding of
the International Conference on New Trends in High Energy Physics, 27 Sept.-4
Oct. 2008, Yalta, Crimea, Ukrain
Extracting Muon Momentum Scale Corrections for Hadron Collider Experiments
We present a simple method for the extraction of corrections for bias in the
measurement of the momentum of muons in hadron collider experiments. Such bias
can originate from a variety of sources such as detector misalignment, software
reconstruction bias, and uncertainties in the magnetic field. The two step
method uses the mean for muons from $Z\to \mu\mu$ decays to
determine the momentum scale corrections in bins of charge, $\eta$ and $\phi$.
In the second step, the corrections are tuned by using the average invariant
mass of events in the same bins of charge
and . The forward-backward asymmetry of pairs
as a function of mass, and the distribution of bosons
in the Collins-Soper frame are used to ascertain that the corrections remove
the bias in the momentum measurements for positive versus negatively charged
muons. By taking the sum and difference of the momentum scale corrections for
positive and negative muons, we isolate additive corrections to
that may originate from misalignments and multiplicative corrections that may
originate from mis-modeling of the magnetic field . This method has recently been used in the CDF experiment at
Fermilab and in the CMS experiment at the Large Hadron Collider at CERNComment: 6 pages, 3 figures, to be published in EPJC 201
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