During 2019 the second release of ATLAS Open Data for educational purposes has been prepared. This release consists of 10 fb$^{-1}$ of $\sqrt{s}$ = 13 TeV data from the ATLAS experiment, along with an extensive set of Monte Carlo simulated samples. In addition to the data, we also release various computing tools, with the aim of making analysis of the dataset more accessible to students....
Buried beneath the South Pole is the world's largest instrumented neutrino detector; IceCube. Inside of IceCube is the DeepCore sub-array, which is a densely instrumented inner region allowing analyses of neutrinos in the ~5-150 GeV energy range. In this talk I will cover some of the recent neutrino oscillations results, such as world-leading measurments of tau neutrino appearance, as well as...
A search for ttbar resonances in the fully hadronic final states is performed using data collected at √s = 13 TeV in 2015-2018, requiring the hadronically decaying top-quarks to be identified using large-radius jets with jet substructure information and associated smaller radius jets identified as originating from b-quarks. The analysis aims to improve the search sensitivity at high mass by...
The possibility of dark matter being a composite particle, such as a hadron under a gauge group, is becoming increasingly appealing as the non-excluded part of parameter space for the WIMP paradigm is shrinking. In this talk I will present a ongoing search for a resonance originating from a QCD-like dark sector, that decays to two dark partons which then hadronise to form ”dark jets”. The...
SHiP is a proposed high-intensity beam dump experiment set to operate at the CERN SPS. It is expected to have an unprecedented sensitivity to a variety of models containing feebly-interacting particles, such as Heavy Neutral Leptons (HNLs). Two HNLs or more could successfully explain the observed neutrino masses through the seesaw mechanism. If, in addition, they are quasi-degenerate, they...
Searching for new physics phenomena in the energy frontier is one of the main goals of the Large Hadron Collider (LHC). The Standard Model of Particle Physics (SM) leaves outstanding questions which can be explored by colliders. Hundreds of searches for new physics have been performed since the LHC inception, but there is no definitive evidence for physics beyond the SM so far.
In recent...
When probed in very high energy collisions hadrons and nuclei are dense gluonic systems. The nonlinear interactions between these gluons can be understood with the color glass condensate effective theory that describes them as a classical color field. This talk will discuss recent advances in using this theoretical framework for scattering processes where the gluon field is probed with a...
The existence of baryon number violating processes is a necessary condition to explain matter-antimatter asymmetry and may also play a role in accessing a hidden sector and addressing the question of dark matter. The construction of the European Spallation Source (ESS) provides a unique opportunity to exploit a high intensity beam of cold neutrons to perform searches for baryon number...
We calculate the total and partial inclusive Higgs widths at leading order in the
Standard Model Effective Field Theory (SMEFT). We report results incorporating SMEFT
corrections for two and four body Higgs decays through vector currents in this limit. The
narrow width approximation is avoided and all phase space integrals are directly evaluated.
We explain why the narrow width...
In particle accelerators, magnetic lenses are used to steer, focus, and control the beam. Typically, these are quadrupole magnets which means that the current must be off-center relative to the beam. Because of this, quadrupole magnets are used for focusing, which must defocus one plane (e.g. vertical) in order to focus the other plane (e.g. horizontal). This complicates optics design and...
The ATLAS Experiment is currently working on a series of upgrades in preparation for the High-Luminosity LHC, which is scheduled to start in 2026. One such upgrade will be to the inner-tracking system. The current Inner Detector will be completely replaced with a brand new, all-silicon Inner Tracker, consisting of a pixel detector near to the beam line and a large-area strip tracking detector....
After measuring in 2012 a relatively large value of the neutrino mixing angle θ13, the door is now open to observe for the first time a possible CP violation in the leptonic sector. The measured value of θ13 also privileges the 2nd oscillation maximum for the discovery of CP violation instead of the usually used 1st oscillation maximum. The sensitivity at this 2nd oscillation maximum is about...
The Standard Model (SM) of particle physics is currently the best theory for describing elementary particles and their interactions, but there are several problems and open questions related to it. For instance it does not incorporate gravity, and it does not explain dark matter, hence there is a need for new fundamental theories of nature beyond the current theory. A theory that addresses...
The plasma wakefield accelerator has demonstrated high-gradient, high-efficiency acceleration of an electron beam. Numerical simulation results backed by theory indicate that also emittance preservation at the level needed for a high luminosity collider may be achievable in the blow out regime. Electron linacs based on plasma wakefield acceleration is therefore a promising technology for a...
At the LHC, the production cross-section for supersymmetric partners of the colored Standard Model particles, namely squarks and gluinos, are expected to be much higher than for the sparticles that do not feel the strong interaction. So far there has been no indication of squarks or gluinos being produced. However, if the colored sparticles are too heavy to be produced at the LHC, we could...
Current Dark Matter (DM) searches at the ATLAS experiment require detailed signal hypotheses for various DM models. In order for a DM analysis to cover a large DM model parameter space, many Monte Carlo (MC) samples might be needed to accurately represent possible signatures/kinematics of the DM model. For complex experiments, such as ATLAS, detector level MC samples are computationally...
ALICE measurements show that strangeness production increases with
multiplicity in small systems (pp and p-Pb collisions) at LHC energies. This
means that one has to give up the idea that a proton-proton collision can be
seen as an incoherent sum of parton-parton collisions; an idea that has been
central in most proton-proton generators, for example PYTHIA. To accommodate
the ALICE...
The primary goal of the ultra-relativistic heavy-ion collision program at the Large Hadron Collider (LHC) is to study the properties of the Quark-Gluon Plasma (QGP), a novel state of strongly interacting matter which exists in the early universe, a few microseconds after Big Bang. Studies of azimuthal correlations of produced particles in ultra-relativistic heavy-ion collision have contributed...
Conventional searches for new phenomena at collider experiments tend to focus on prompt particles, produced at the interaction point and decaying rapidly. New physics models including long-lived particles that travel a substantial distance in the detectors before decaying provide an interesting alternative, especially in light of the lack of new phenomena at the current LHC experiments, and...
The Large Hadron Collider (LHC) at CERN announced the High-Luminosity LHC (HL-LHC) project in 2013 with the aim of increasing the machine performance for new physics discoveries. Researchers will take full advantage of HL-LHC to study known mechanisms in greater detail and observe rare new physics phenomena. HL-LHC poses some challenges on all the LHC experiments: a ten times higher readout...
Study of the neutron and nuclear beta decay correlation coefficients play important role in understanding the weak interaction. The correlation coefficients are sensitive to the exotic scalar and tensor interactions that are not included in the Standard Model. The information from low energy precision experiments is often complementary to that obtained from high-energy scale experiments. A...
Radiation hard pixel ‘3D’ sensors for use in ATLAS-ITk at LHC
The signal to background ratio for Higgs decaying to 2 photons is small, therefore, a powerful estimation of the background is needed to accurately measure the signal. Since the underlying physical function is unknown, various functional parameterizations are considered for background estimation. When the number of events increases, the relative uncertainty decreases. This might give rise to...
In connection with the High Luminosity upgrade of the Large Hardron Collider, the current ATLAS Inner Detector will be replaced by a new all silicon detector - the Inner Tracker ITk. The ITk will use Silicon pixel and microstrip sensor technology across two primary geometries, a central barrel-like structure and two sets of wheels acting as end-caps for the detector. The Scandinavian ITk...
Hand in hand with the large-scale experimental attempts to observe traces of supersymmetry at the LHC, there are ongoing efforts to assess the combined power of all searches so far. Such global fits to experimental results require accurate theoretical predictions of the production cross sections for supersymmetric particles. However, computing higher-order contributions is prohibitively...