Single top-quark production, accounting for ∼1/3 of the overall top-quark production at the LHC, constitutes an excellent probe of the W-t-b coupling, which is sensitive to certain types of new ...physics. One important production mode in the Standard Model is the creation of a single top quark in association with a W boson. The close similarity of its final state to that of top-quark pair production, which has a more than 10 times larger production cross-section, makes the measurement a challenging endeavour. Hence multivariate techniques are appropriate to identify the Wt signal. The results of the latest Wt cross-section measurement with the ATLAS detector, based on 20 fb−1 of pp-collision data at s=8 TeV, are presented.
Production of exclusive dijets in diffractive deep inelastic Formula omitted scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 372 pb Formula omitted. The ...measurement was performed for Formula omitted-p centre-of-mass energies in the range Formula omitted and for photon virtualities Formula omitted. Energy flows around the jet axis are presented. The cross section is presented as a function of Formula omitted and Formula omitted, where Formula omitted, x is the Bjorken variable and Formula omitted is the proton fractional longitudinal momentum loss. The angle Formula omitted is defined by the Formula omitted-dijet plane and the Formula omitted- Formula omitted plane in the rest frame of the diffractive final state. The Formula omitted cross section is measured in bins of Formula omitted. The results are compared to predictions from models based on different assumptions about the nature of the diffractive exchange.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
The photoproduction of
D
∗±
mesons has been measured with the ZEUS detector at HERA at three different
ep
centre-of-mass energies,
s
, of 318, 251 and 225 GeV. For each data set,
D
∗±
...mesons were required to have transverse momentum,
p
T
D
∗
, and pseudo-rapidity,
η
D
∗
, in the ranges 1
.
9
< p
T
D
∗
<
20 GeV and |
η
D
∗
|
<
1
.
6. The events were required to have a virtuality of the incoming photon,
Q
2
, of less than 1 GeV
2
. The dependence on
s
was studied by normalising to the high-statistics measurement at
s
=
318
GeV. This led to the cancellation of a number of systematic effects both in data and theory. Predictions from next-to-leading-order QCD describe the
s
dependence of the data well.
The neutral current ${e}^{±}p$ cross section has been measured up to values of Bjorken $x\cong 1$ with the ZEUS detector at HERA using an integrated luminosity of ...$187\text{}\text{}{\mathrm{pb}}^{-1}$ of ${e}^{-}p$ and $142\text{}\text{}{\mathrm{pb}}^{-1}$ of ${e}^{+}p$ collisions at $\sqrt{s}=318\text{}\text{}\mathrm{GeV}$. Differential cross sections in $x$ and ${Q}^{2}$, the exchanged boson virtuality, are presented for ${Q}^{2}\ge 725\text{}\text{}{\mathrm{GeV}}^{2}$. An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-$x$ region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.
Although surgical treatment of patients on anticoagulation regimens is common practice among oral and maxillofacial surgeons, unexpected and unknown coagulopathies can have devastating and ...catastrophic consequences for the most routine of procedures. Acquired hemophilia A (AHA) is an extremely rare life-threatening bleeding disorder characterized by autoantibodies directed against circulating coagulation factor VIII. The effects of AHA can produce catastrophic bleeding and hematomas. The effect of this uncontrolled hemorrhage after dentoalveolar surgery can mimic severe head and neck infection by causing dysphagia, odynophagia, and acute airway complications. This report describes the case of a 64-year-old woman who was diagnosed with AHA after routine extraction of the mandibular left third molar.
Recent measurements of open charm and beauty photoproduction with the H1 and ZEUS detectors at the e±p-collider HERA are presented. These measurements reveal valuable details about the inner ...structure of the proton and the photon, the fragmentation of quarks into jets, and allow tests of perturbative QCD. Various experimental techniques were employed to identify and extract the heavy-quark signal. Their results are discussed, and compared to each other and to NLO QCD calculations. In addition the determination of charm fragmentation fractions is presented.
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