Simulating hard photon production with Whizard Kalinowski, J.; Kotlarski, W.; Sopicki, P. ...
The European physical journal. C, Particles and fields,
07/2020, Letnik:
80, Številka:
7
Journal Article
Recenzirano
Odprti dostop
One of the important goals of the proposed future
e
+
e
-
collider experiments is the search for dark matter particles using different experimental approaches. The most general search approach is ...based on the mono-photon signature, which is expected when production of the invisible final state is accompanied by a hard photon from initial state radiation. Analysis of the energy spectrum and angular distributions of those photons can shed light on the nature of dark matter and its interactions. Therefore, it is crucial to be able to simulate the signal and background samples in a uniform framework, to avoid possible systematic biases. The
Whizard
program is a flexible tool, which is widely used by
e
+
e
-
collaborations for simulation of many different “new physics” scenarios. We propose the procedure of merging the matrix element calculations with the lepton ISR structure function implemented in
Whizard
. It allows us to reliably simulate the mono-photon events, including the two main Standard Model background processes: radiative neutrino pair production and radiative Bhabha scattering. We demonstrate that cross sections and kinematic distributions of mono-photon in neutrino pair-production events agree with corresponding predictions of the
KK
MC, a Monte Carlo generator providing perturbative predictions for SM and QED processes, which has been widely used in the analysis of LEP data.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A new way to improve organic white‐light‐emitting‐diodes is reported. Their emissive layers are unique in that three different emissive states are produced efficiently at the same time (see scheme). ...The combined emission band enables us to form an efficient white device with particularly high color rendering index of CRI=90.
A
bstract
We perform a comprehensive analysis of a version of the 3-Higgs doublet model whose scalar potential is invariant under a global ∆(27) discrete symmetry and where the three scalar doublets ...are chosen to transform as a triplet under this discrete group. For each of the known tree-level minima we study the mass spectra and use the oblique parameters
STU
as well as perturbative unitarity to constrain the parameter space of the model. We then discuss phenomenological consequences of some leading order flavour mixing quark Yukawa couplings by considering the flavour violation process
b
→
sγ
.
We show that perturbative unitarity significantly constrains parameters of the model while, conversely, the beyond the Standard Model contributions to the
b
→
sγ
decay are automatically tamed by the symmetry.
The article provides a brief review of typical classes of optical materials for organic light-emitting-devices (LEDs) that includes fluorescent materials, phosphors, electron donor–acceptor and ...line-like emitting molecular systems. The emphasis is on low-molecular weight materials though the role of polymers is mentioned. A great deal of progress in improving efficiency and spectral properties of organic LEDs is demonstrated based on analyses of electronic processes in organic optical materials.
The search for renormalization group invariant relations among parameters to all orders in perturbation theory constitutes the basis of the reduction of couplings concept. Reduction of couplings can ...be achieved in certain
N
=
1
supersymmetric grand unified theories and few of them can become even finite at all loops. We review the basic idea, the tools that have been developed as well as the resulting theories in which successful reduction of couplings has been achieved so far. These include: (i) a reduced version of the minimal
N
=
1
S
U
(
5
)
model, (ii) an all-loop finite
N
=
1
S
U
(
5
)
model, (iii) a two-loop finite
N
=
1
S
U
(
3
)
3
model and finally (vi) a reduced version of the Minimal Supersymmetric Standard Model. In this paper we present a number of benchmark scenarios for each model and investigate their observability at existing and future hadron colliders. The heavy supersymmetric spectra featured by each of the above models are found to be beyond the reach of the 14 TeV HL-LHC. It is also found that the reduced version of the MSSM is already ruled out by the LHC searches for heavy neutral MSSM Higgs bosons. In turn the discovery potential of the 100 TeV FCC-hh is investigated and found that large parts of the predicted spectrum of these models can be tested, but the higher mass regions are beyond the reach even of the FCC-hh.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Physics at the e+e- linear collider Moortgat-Pick, G.; Baer, H.; Battaglia, M. ...
The European physical journal. C, Particles and fields,
08/2015, Letnik:
75, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A comprehensive review of physics at an
e
+
e
-
linear collider in the energy range of
s
=
92
GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well ...as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Sample pooling is a promising strategy to facilitate COVID-19 surveillance testing for a larger population in comparison to individual single testing due to resource and time constraints. Increased ...surveillance testing capacity will reduce the likelihood of outbreaks as the general population is returning to work, school, and other gatherings. We have analyzed the impact of three variables on the effectiveness of pooling test samples: swab type, workflow, and positive sample order. We investigated the performance of several commercially available swabs (Steripack polyester flocked, Puritan nylon flocked, Puritan foam) in comparison to a new injected molded design (Yukon). The bench-top performance of collection swab was conducted with a previously developed anterior nasal cavity tissue model, based on a silk-glycerol sponge to mimic soft tissue mechanics and saturated with a physiologically relevant synthetic nasal fluid spiked with heat-inactivated SARS-CoV-2. Overall, we demonstrated statistically significant differences in performance across the different swab types. A characterization of individual swab uptake (gravimetric analysis) and FITC microparticle release suggests that differences in absorbance and retention drive the observed differences in Ct of the pooled samples. We also proposed two distinct pooling workflows to encompass different community collection modes and analyzed the difference in resulting positive pools as an effect of workflow, swab type, and positive sample order. Overall, swab types with lower volume retention resulted in reduced false negative occurrence, also observed for collection workflows with limited incubation times. Concurrently, positive sample order did have a significant impact on pooling test outcome, particularly in the case of swab type with great volume retention. We demonstrated that the variables investigated here affect the results of pooled COVID-19 testing, and therefore should be considered while designing pooled surveillance testing.
Recent progress in "on-the-fly" trajectory simulations of molecular reactions, using different electronic structure methods is discussed, with analysis of the insights that such calculations can ...provide and of the strengths and limitations of the algorithms available. New developments in the use of both
ab initio
and semi-empirical electronic structure algorithms are described. The emphasis is on: (i) calculations of electronic properties along the reactive trajectories and the unique insights this can contribute to the processes; (ii) electronic structure methods recently introduced to this topic to improve accuracy, extend applicability or enhance computational efficiency. The methods are presented with examples, including new results, of reactions of both isolated molecules and of molecules in media, mostly clusters. Possible future directions for this fast growing field are suggested.
Recent progress in "on-the-fly" trajectory simulations of molecular reactions, using different electronic structure methods is discussed, with analysis of the insights that such calculations can provide and of the strengths and limitations of the algorithms available.
We discuss the status of the Inert Doublet Model, a two-Higgs doublet model that obeys a discrete Z2 symmetry and provides a dark matter candidate. We discuss all current theoretical and experimental ...constraints on the model as well as discovery prospects at current and future colliders.
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