Organic-based photovoltaics (PV) have attracted increasing attention in recent years and efficiencies exceeding 8% have recently been confirmed. These low cost, lightweight and mechanically flexible ...devices offer unique advantages and opportunities currently unavailable with crystalline silicon technology. Progress in the field of organic PV has been achieved in part due to the incorporation of transition metal oxides. These offer a wide range of optical and electronic properties, making them applicable in organic-based PV in many capacities. Transparent electrodes can be made from doped metal oxides. The high intrinsic charge carrier mobility of many undoped metal oxides makes them attractive as active materials and charge collectors. Metal oxides can increase the charge selectivity of the electrodes due to the energetic positioning of their valence and conduction bands. Thin films of these materials can manipulate the light distribution inside of organic devices, allowing for improved light harvesting. Metal oxides are stable and can be processed at low temperatures. Consequently, they have been demonstrated as suitable intermediate layer materials in tandem cells. Finally, oxygen-deficient metal oxides can improve the stability of the oxygen- sensitive organic semiconductors. The present work reviews the various applications of metal oxide layers in organic PV devices and summarises the challenges associated with organic/oxide interfaces.
A
bstract
The recent discovery, by the LHCb collaboration, of the Ξ
cc
+ +
doubly charmed baryon, has renewed interest in the spectroscopy of doubly heavy hadrons. Experimentally, however, searches ...for such states appear highly challenging. The reconstructed final states tend to involve multiple heavy flavoured (beauty or charm) hadrons, so the yield for any exclusive decay mode will be suppressed to unobservably low levels by the product of several branching fractions, each of which is typically 10
−3
–10
−2
. Noting that decays of double beauty hadrons are the only possible source of
B
c
−
mesons that are displaced from the primary vertices of proton-proton collisions at the LHC, a more promising inclusive search strategy is proposed.
Recent studies of several multi-body D0 meson decays have revealed that the final states are dominantly CP-even. However, the small value of the width difference between the two physical eigenstates ...of the D0–D‾0 system indicates that the total widths of decays to CP-even and CP-odd final states should be the same to within about a percent. The known contributions to the width difference from hadronic D0 decays are discussed, and it is shown that an apparent excess of quasi-CP-even modes is balanced, within current uncertainty, by interference effects in quasi-flavour-specific decays. Decay modes which may significantly affect the picture with improved measurements are considered.
This article reports world averages of measurements of
b
-hadron,
c
-hadron, and
τ
-lepton properties obtained by the Heavy Flavor Averaging Group using results available through summer 2016. For the ...averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters,
C
P
violation parameters, parameters of semileptonic decays, and Cabbibo–Kobayashi–Maskawa matrix elements.
Weak decays of the vector
D
∗
0
and
B
(
s
)
∗
0
mesons to the
μ
+
μ
-
final state provide novel potential to test the Standard Model of particle physics. Such processes have extremely small branching ...fractions as the vector mesons are able to decay through electromagnetic and (for the
D
∗
0
meson) strong interactions. Nonetheless, the production of copious quantities of these particles in LHC collisions, and the ability to exploit experimental techniques that can suppress background to low levels, provides good potential to reach interesting sensitivity. The possibility to reconstruct these processes as part of the decay chain of
B
-
or
B
c
+
mesons appears particularly attractive due to the clean experimental signature of the displaced vertex. Indeed, published LHCb data on
B
-
→
π
-
μ
+
μ
-
decays already implies a stringent limit on the branching fraction of
D
∗
0
→
μ
+
μ
-
. Estimates are made on the achievable sensitivity to
D
∗
0
→
μ
+
μ
-
and
B
(
s
)
∗
0
→
μ
+
μ
-
decays with the LHCb experiment.
We propose a novel method to measure flavor oscillations and charge-parity ( C P ) violation in charm mixing. The approach applies to multibody charm decays, such as D0 → K0Sπ+π−, and avoids the need ...for a fit of the decay amplitudes while suppressing biases due to nonuniform signal reconstruction efficiencies as functions of phase space and decay time. Data are partitioned in decay-time and Dalitz-plot regions (bins). The Dalitz-plot bins are symmetric with respect to the principal bisector and chosen to ensure nearly constant values of the strong interaction phases in each. The ratios of signal yields observed in each symmetric bin pair are fit as functions of decay time, using independent auxiliary measurements of the strong interaction phases as constraints, to determine the relevant physics parameters. Simulation shows a 35% improvement in sensitivity to the normalized charm-eigenstate mass difference with respect to existing model-independent methods. In addition, we introduce a parametrization of oscillation and CP-violation effects in charm mixing that has attractive statistical properties and may find wider applicability.
Rare b Hadron Decays at the LHC Blake, T; Gershon, T; Hiller, G
Annual review of nuclear and particle science,
10/2015, Letnik:
65, Številka:
1
Journal Article
Recenzirano
Odprti dostop
With the completion of Run I of the CERN Large Hadron Collider, particle physics has entered a new era. The production of unprecedented numbers of heavy-flavored hadrons in high-energy proton-proton ...collisions allows detailed studies of flavor-changing processes. The increasingly precise measurements allow the Standard Model to be tested with a new level of accuracy. Rare
b
hadron decays provide some of the most promising approaches for such tests because there are several observables that can be cleanly interpreted from a theoretical viewpoint. In this article, we review the status and prospects in this field, with a focus on precision measurements and null tests.
Performance of a prototype TORCH time-of-flight detector Bhasin, S.; Blake, T.; Brook, N.H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2023, Letnik:
1050
Journal Article
Recenzirano
Odprti dostop
TORCH is a novel time-of-flight detector, designed to provide charged particle identification of pions, kaons and protons in the momentum range 2–20 GeV/c over a 9.5 m flight path. A detector module, ...comprising a 10 mm thick quartz plate, provides a source of Cherenkov photons which propagate via total internal reflection to one end of the plate. Here, the photons are focused onto an array of custom-designed Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMTs) which measure their positions and arrival times. The target time resolution per photon is 70 ps which, for 30 detected photons per charged particle, results in a 10–15 ps time-of-flight resolution. A 1.25 m length TORCH prototype module employing two MCP-PMTs has been developed, and tested at the CERN PS using a charged hadron beam of 8 GeV/c momentum. The construction of the module, the properties of the MCP-PMTs and the readout electronics are described. Measurements of the collected photon yields and single-photon time resolutions have been performed as a function of particle entry points on the plate and compared to expectations. These studies show that the performance of the TORCH prototype approaches the design goals for the full-scale detector.
TORCH pattern recognition and particle identification performance Garcia Martin, L.M.; Blake, T.; Brook, N.H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2023, Letnik:
1055
Journal Article
Recenzirano
Odprti dostop
The TORCH detector aims to provide K/π (K/p) separation up to a momentum of about 10 (15) ▪ by measuring their time-of-flight at the LHCb detector. Prompt Cherenkov photons are produced in a quartz ...radiator bar of 10 mm thickness, and propagated via total internal reflection to the periphery of the detector, where they are focused onto an array of microchannel plate photomultipliers that measure the photon arrival time and position. Pattern recognition techniques are used to compare the likelihood that the detector image is due to a given particle hypothesis. Good performance is obtained even for very high detector occupancies.
The TORCH time-of-flight detector Harnew, N.; Gao, R.; Hadavizadeh, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2023, Letnik:
1048
Journal Article
Recenzirano
Odprti dostop
TORCH is a large-area time-of-flight (ToF) detector, proposed for the Upgrade-II of the LHCb experiment. It will provide charged hadron identification over a 2–20 GeV/c momentum range, given a 9.5m ...flight distance from the LHC interaction point. To achieve this level of performance, a 15ps timing resolution per track is required. A TORCH prototype module having a 1250×660×10mm3 fused-silica radiator plate and equipped with two MCP-PMTs has been tested in a 8GeV/c CERN test-beam. Single-photon time resolutions of between 70–100ps have been achieved, dependent on the beam position in the radiator. The measured photon yields agree with expectations.
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