The strong coupling constant
α
s
is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic
ep
scattering (DIS) measured at HERA by the H1 collaboration using ...next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of
α
s
(
m
Z
)
at the
Z
-boson mass
m
Z
are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be
α
s
(
m
Z
)
=
0.1157
(
20
)
exp
(
29
)
th
. Complementary,
α
s
(
m
Z
)
is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value
α
s
(
m
Z
)
=
0.1142
(
28
)
tot
obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.
A detailed investigation of hadronic interactions is performed using π−-mesons with energies in the range 2–10 GeV incident on a high granularity silicon–tungsten electromagnetic calorimeter. The ...data were recorded at FNAL in 2008. The region in which the π−-mesons interact with the detector material and the produced secondary particles are characterised using a novel track-finding algorithm that reconstructs tracks within hadronic showers in a calorimeter in the absence of a magnetic field. The principle of carrying out detector monitoring and calibration using secondary tracks is also demonstrated.
We present a study of the response of the highly granular Digital Hadronic Calorimeter with steel absorbers, the Fe-DHCAL, to positrons, muons, and pions with momenta ranging from 2 to 60GeV/c. ...Developed in the context of the CALICE collaboration, this hadron calorimeter utilises Resistive Plate Chambers as active media, interspersed with steel absorber plates. With a transverse granularity of 1×1cm2 and a longitudinal segmentation of 38 layers, the calorimeter counted 350,208 readout channels, each read out with single-bit resolution (digital readout). The data were recorded in the Fermilab test beam in 2010–11. The analysis includes measurements of the calorimeter response and the energy resolution to positrons and muons, as well as detailed studies of various shower shape quantities. The results are compared to simulations based on Geant4, which utilise different electromagnetic and hadronic physics lists.
A highly granular electromagnetic calorimeter with scintillator strip readout is being developed for future linear collider experiments. A prototype of 21.5 X0 depth and 180×180mm2 transverse ...dimensions was constructed, consisting of 2160 individually read out 10×45×3mm3 scintillator strips. This prototype was tested using electrons of 2–32 GeV at the Fermilab Test Beam Facility in 2009. Deviations from linear energy response were less than 1.1%, and the intrinsic energy resolution was determined to be (12.5±0.1(stat.)±0.4(syst.))%∕EGeV⊕(1.2±0.1(stat.)−0.7+0.6(syst.))%, where the uncertainties correspond to statistical and systematic sources, respectively.
The latest developments of calorimeters using scintillators as active medium for detectors at the ILC are reviewed. We mention those having already a prototype that was tested in the beam. Besides ...classical scintillator tile calorimeters with smallest tiles ever used, a completely new approach was proposed with independent measurement of scintillation and Cherenkov light produced in fibers. Special attention is given to new photodetectors - silicon photomultipliers - which have been extensively used for the scintillator readout. Their main advantages are a high gain ~10 6 at a low bias voltage 55-75 V, easy integration into a scintillator and a reasonable price.
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