The LHCb detector has undergone a major upgrade for LHCRun 3. This Upgrade I detector facilitates operation at higherluminosity and utilises full-detector information at the LHCcollision rate, ...critically including the use of vertexinformation. A new vertex locator system, the VELO Upgrade, has beenconstructed. The core element of the new VELO are the double-sidedpixelated hybrid silicon detector modules which operate in vacuumclose to the LHC beam in a high radiation environment. Theconstruction and quality assurance tests of these modules aredescribed in this paper. The modules incorporate200 μm thick, n-on-p silicon sensors bump-bonded to130 nm technology ASICs. These are attached with high precision toa silicon microchannel substrate that uses evaporative CO2 cooling. The ASICs are controlled and read out with flexible printedcircuits that are glued to the substrate and wire-bonded to thechips. The mechanical support of the module is given by a carbonfibre plate, two carbon fibre rods and an aluminium plate. Thesensor attachment was achieved with an average precision of21 μm, more than 99.5% of all pixels are fullyfunctional, and a thermal figure of merit of3 Kcm2W-1 was achieved. The production of themodules was successfully completed in 2021, with the final assemblyand installation completed in time for data taking in 2022.
The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in 208Tl and 214Bi for the SuperNEMO double beta decay source foils. A modular prototype, called ...BiPo-1, with 0.8m2 of sensitive surface area, has been running in the Modane Underground Laboratory since February, 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in 208Tl. After more than one year of background measurement, a surface activity of the scintillators of A(Tl208)=1.5μBq/m2 is reported here. Given this level of background, a larger BiPo detector having 12m2 of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A(Tl208)<2μBq/kg (90% C.L.) with a six month measurement.
The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double
β
decay experiment SuperNEMO is ...discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double
β
decay by measuring the decay half-life and the electron angular and energy distributions.
Charmless b-hadron decays at LHCb Nasteva, Irina
Suplemento de la Revista Mexicana de Física,
06/2022, Letnik:
3, Številka:
3
Journal Article
Measurements of CP asymmetries in charmless two-body B-meson decays can provide stringent tests of the Standard Model. In multibody decays, short and long-distance dynamics along with a sizeable ...effective weak phase in the interference between tree and penguin amplitudes can lead to a rich structure of CP violation as a function of the phase space. We present here the latest studies of CP violation in charmless b-hadron decays, in particular those with baryons in the initial and final states.
Using 9.4 g of
96Zr isotope and 1221 days of data from the NEMO-3 detector corresponding to 0.031 kg y, the obtained
2
ν
β
β
decay half-life measurement is
T
1
/
2
2
ν
=
2.35
±
0.14
(
stat
)
±
0.16
...(
syst
)
×
10
19
yr
. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2
ν nuclear matrix element is extracted using the measured
2
ν
β
β
half-life and is
M
2
ν
=
0.049
±
0.002
. Constraints on
0
ν
β
β
decay have also been set.
We present a detailed study of the central exclusive production of the standard model Higgs boson in the WW decay channel at the LHC. We include estimates of the experimental acceptance, including ...that of the proposed proton tagging detectors at 220 m and 420 m around either ATLAS and/or CMS, and the level 1 trigger acceptances. We give first estimates of the photon-photon and glue-glue background processes in the semi-leptonic and fully leptonic decay channels. We find that there will be a detectable signal for Higgs masses between 140 GeV and 200 GeV, and that the backgrounds should be controllable.
CMS experiment will use resistive plate chambers (RPCs) as dedicated muon trigger detectors. This requires good chamber global and local performance. To verify the chamber performance intensive tests ...are going on using a telescope installed at Bari Physics Department. The chamber efficiency is obtained by track reconstruction, which offers also the possibility to perform local efficiency studies. A brief description of the test set-up, reconstruction algorithm and test results are presented in this paper.
The Large Hadron Collider beauty (LHCb) detector is designed to detect decays of b- and c- hadrons for the study of CP violation and rare decays. At the end of the LHC Run 2, many of the LHCb ...measurements remained statistically dominated. In order to increase the trigger yield for purely hadronic channels, the hardware trigger will be removed, and the detector will be read out at 40 MHz. This, in combination with the five-fold increase in luminosity, requires radical changes to LHCb's electronics, and, in some cases, the replacement of entire sub-detectors with state-of-the-art detector technologies. The Vertex Locator (VELO) surrounding the interaction region is used to reconstruct the collision points (primary vertices) and decay vertices of long-lived particles (secondary vertices). The upgraded VELO will be composed of 52 modules placed along the beam axis divided into two retractable halves. The modules will each be equipped with 4 silicon hybrid pixel tiles, each read out by 3 VeloPix ASICs. The total output data rate anticipated for the whole detector will be around 1.6 Tbit/s. The highest occupancy ASICs will have pixel hit rates of approximately 900 Mhit/s, with the corresponding output data rate of 15 Gbit/s. The LHCb upgrade detector will be the first detector to read out at the full LHC rate of 40 MHz. The VELO upgrade will utilize the latest detector technologies to read out at this rate while maintaining the required radiation-hard profile and minimizing the detector material.
Measurement of the background in the NEMO 3 double beta decay experiment Argyriades, J.; Arnold, R.; Augier, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2009, Letnik:
606, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In the double beta decay experiment NEMO 3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO 3 to evaluate the ...backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.
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