The sensitivities to anomalous quartic photon couplings at the Large Hadron Collider are estimated using diphoton production via photon fusion. The tagging of the protons proves to be a very powerful ...tool to suppress the background and unprecedented sensitivities down to 7 x 10 super(-15) GeV-4 are obtained, providing a new window on extra dimensions and strongly interacting composite states in the multi-TeV range. Generic contributions to quartic photon couplings from charged and neutral particles with arbitrary spin are also presented.
Under certain running conditions, the CERN Large Hadron Collider (LHC) can be considered as a photon–photon collider. Indeed, in proton–proton, proton–ion, ion–ion collisions, when incoming particles ...pass very close to each other in very peripheral collisions, the incoming protons or ions remain almost intact and continue their path along the beam axis. Then, only the electromagnetic (EM) fields of these ultra-relativistic charged particles (protons or ions) interact to leave a signature in the central detectors of the LHC experiments. The interest is that the photon–photon interactions happen at unprecedented energies (a few TeV per nucleon pairs) where the quantum electrodynamics (QED) theory can be tested in extreme conditions and unforeseen laws of nature could be discovered. In this report, we propose a focus on a particular reaction, called light-by-light scattering in which two incoming photons interact, producing another pair of photons. We describe how experimental results have been obtained at the LHC. In addition, we discuss prospects for on-shell photon–photon interactions in dedicated laser beam facilities. Potential signatures of new physics might manifest as resonant deviations in the refractive index, induced by anomalous light-by-light scattering effects. Importantly, we explain how this process can be used to probe the physics beyond the standard model such as theories that include large extra dimensions. Finally, some perspectives and ideas are given for future data taking or experiments.
CentOS Linux for the ATLAS MUCTPI Upgrade Spiwoks, R.; Armbruster, A.; Czodrowski, P. ...
IEEE transactions on nuclear science,
08/2021, Letnik:
68, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A new Muon-to-Central-Trigger Processor Interface (MUCTPI) was built as part of the upgrade of the ATLAS Level-1 trigger system for the next Run of the Large Hadron Collider at CERN. The MUCTPI has ...208 high-speed optical serial links for receiving muon candidates from the muon trigger detectors. Three high-end field-programmable gate arrays (FPGAs) are used for real-time processing of the muon candidates, for sending trigger information to other parts of the trigger system, and for sending summary information to the data acquisition and monitoring system. A System-on-Chip (SoC) is used for the control, configuration, and monitoring of the hardware and the operation of the MUCTPI. The SoC consists of an FPGA part and a processor system (PS). The FPGA part provides communication with the processing FPGAs, while the PS runs software for communication with the run-control system of the ATLAS experiment. In this article, we will describe our experience with running CentOS Linux on the SoC. Cross-compilation together with the existing framework for building the ATLAS trigger and data acquisition (TDAQ) software is being used in order to allow the deployment of the TDAQ software directly on the SoC.
Primordial or big bang nucleosynthesis (BBN) is one of the three strong pieces of evidence for the big bang model together with the expansion of the universe and cosmic microwave background ...radiation. In this study, we improve the standard BBN calculations taking into account new nuclear physics analyses and enlarge the nuclear network up to sodium. This is, in particular, important to evaluate the primitive value of CNO mass fraction that could affect Population III stellar evolution. For the first time we list the complete network of more than 400 reactions with references to the origin of the rates, including approx =270 reaction rates calculated using the TALYS code. Together with the cosmological light elements, we calculate the primordial beryllium, boron, carbon, nitrogen, and oxygen nuclei. We performed a sensitivity study to identify the important reactions for CNO, super(9)Be, and boron nucleosynthesis. We re-evaluated those important reaction rates using experimental data and/or theoretical evaluations. The results are compared with precedent calculations: a primordial beryllium abundance increase by a factor of four compared to its previous evaluation, but we note a stability for B/H and for the CNO/H abundance ratio that remains close to its previous value of 0.7 x 10 super(-15). On the other hand, the extension of the nuclear network has not changed the super(7)Li value, so its abundance is still 3-4 times greater than its observed spectroscopic value.
The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to ...digital converter and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to improve time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using pulses generated by a signal generator or by a silicon detector illuminated by a pulsed infrared laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4ps with synthesized signals and 40ps with silicon detector signals.
We consider hard diffractive events in proton-proton collisions at the LHC, in which both protons escape the collision intact. In such double Pomeron exchange processes, we propose to measure dijets ...and photon-jet final states, and we show that it has the potential to pin down the Pomeron quark and gluon contents, a crucial ingredient in the standard QCD description of hard diffraction. By comparing with predictions of the soft color interaction approach, we also show that more generally, the measurement of the photon-jet to dijet cross section ratio can put a stringent test on the QCD dynamics at play in diffractive processes in hadronic collisions.
The SAMPIC Waveform and Time to Digital Converter Delagnes, E.; Breton, D.; Grabas, H. ...
2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC),
11/2014
Conference Proceeding
Odprti dostop
SAMPIC is a Waveform and Time to Digital Converter (WTDC) multichannel chip. Each of its 16 channels associates a DLL-based TDC providing a raw time with an ultra-fast analog memory allowing fine ...timing extraction as well as other parameters of the pulse. Each channel also integrates a discriminator that can trigger itself independently or participate to a more complex trigger. After triggering, analog data is digitized by an on-chip ADC and only that corresponding to a region of interest is sent serially to the DAQ. The association of the raw and fine timings permits achieving timing resolutions of a few ps rms. The paper describes the detailed SAMPIC0 architecture and reports its main measured performances.
Under certain running conditions, the CERN Large Hadron Collider (LHC) can be considered as a photon-photon collider. Indeed, in proton-proton, proton-ion, ion-ion collisions, when incoming particles ...pass very close to each other in very peripheral collisions, the incoming protons or ions remain almost intact and continue their path along the beam axis. Then, only the electromagnetic (EM) fields of these ultra-relativistic charged particles (protons or ions) interact to leave a signature in the central detectors of the LHC experiments. The interest is that the photon-photon interactions happen at unprecedented energies (a few TeV per nucleon pairs) where the quantum electrodynamics (QED) theory can be tested in extreme conditions and unforeseen laws of nature could be discovered. In this report, we propose a focus on a particular reaction, called light-by-light scattering in which two incoming photons interact, producing another pair of photons. We describe how experimental results have been obtained at the LHC. In addition, we discuss prospects for on-shell photon-photon interactions in dedicated laser beam facilities. Potential signatures of new physics might manifest as resonant deviations in the refractive index, induced by anomalous light-by-light scattering effects. Importantly, we explain how this process can be used to probe the physics beyond the standard model such as theories that include large extra dimensions. Finally, some perspectives and ideas are given for future data taking or experiments.
We consider hard diffractive events in proton-proton collisions at the LHC, in which both protons escape the collision intact. In such double Pomeron exchange processes, we propose to measure dijets ...and photon-jet final states, and we show that it has the potential to pin down the Pomeron quark and gluon contents, a crucial ingredient in the standard QCD description of hard diffraction. By comparing with predictions of the soft color interaction approach, we also show that more generally, the measurement of the photon-jet to dijet cross section ratio can put a stringent test on the QCD dynamics at play in diffractive processes in hadronic collisions.
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