The International Linear Collider (ILC) will allow the precise study of
e
-
e
+
→
q
q
¯
interactions at different center-of-mass energies from the
Z
-pole to 1 TeV. In this paper, we discuss the ...experimental prospects for measuring differential observables in
e
-
e
+
→
b
b
¯
and
e
-
e
+
→
c
c
¯
at the ILC baseline energies, 250 and 500 GeV. The study is based on full simulation and reconstruction of the International Large Detector (ILD) concept. Two gauge-Higgs unification models predicting new high-mass resonances beyond the Standard Model are discussed. These models predict sizable deviations of the forward–backward observables at the ILC running above the
Z
mass and with longitudinally polarized electron and positron beams. The ability of the ILC to probe these models via high-precision measurements of the forward–backward asymmetry is discussed. Alternative scenarios at other energies and beam polarization schemes are also discussed, extrapolating the estimated uncertainties from the two baseline scenarios.
Conceptual design report for the LUXE experiment Abramowicz, H.; Acosta, U.; Altarelli, M. ...
The European physical journal. ST, Special topics,
2021, Letnik:
230, Številka:
11
Journal Article
Recenzirano
Odprti dostop
This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a ...powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout.
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 technological prototype of the CALICE highly granular silicon–tungsten electromagnetic calorimeter (SiW-ECAL) was tested in a beam at DESY in 2017. The setup comprised seven layers of silicon ...sensors. Each layer comprised four sensors, with each sensor containing an array of 256 5.5×5.5 mm2 silicon PIN diodes. The four sensors covered a total area of 18 × 18 cm and comprised a total of 1024 channels. The readout was split into a trigger line and a charge signal line. Key performance results for signal over noise for the two output lines are presented, together with a study of the uniformity of the detector response. Measurements of the response to electrons for the tungsten loaded version of the detector are also presented.
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.
Top quark production in the process
e
+
e
-
→
t
t
¯
at a future linear electron positron collider with polarised beams is a powerful tool to determine indirectly the scale of new physics. The ...presented study, based on a detailed simulation of the ILD detector concept, assumes a centre-of-mass energy of
s
=
500
GeV and a luminosity of
L
=
500
fb
-
1
equally shared between the incoming beam polarisations of
P
e
-
,
P
e
+
=
±
0.8
,
∓
0.3
. Events are selected in which the top pair decays semi-leptonically and the cross sections and the forward–backward asymmetries are determined. Based on these results, the vector, axial vector and tensorial
CP
conserving couplings are extracted separately for the photon and the
Z
0
component. With the expected precision, a large number of models in which the top quark acts as a messenger to new physics can be distinguished with many standard deviations. This will dramatically improve expectations from e.g. the LHC for electro-weak couplings of the top quark.
An experiment (E166) at the Stanford Linear Accelerator Center has demonstrated a scheme in which a multi-GeV electron beam passed through a helical undulator to generate multi-MeV, circularly ...polarized photons which were then converted in a thin target to produce positrons (and electrons) with longitudinal polarization above 80% at 6 MeV. The results are in agreement with GEANT4 simulations that include the dominant polarization-dependent interactions of electrons, positrons, and photons in matter.
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