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Probing physics in the standard model and beyond with electroweak baryogenesis and effective theories of the strong interactions

Probing physics in the standard model and beyond with electroweak baryogenesis and effective theories of the strong interactions

separate the Standard Model background in such processes in searches for new physics. Universalities among nonperturbative contributions to different event shapes would reduce the uncertainties in these calcualtions greatly, improving our ability to find deviations from Standard Model predictions while also revealing new information about QCD itself. We attempted to find such relations in the Z decay distributions in jet energy, thrust, jet masses, jet broadenings, C parameter, and other variables. The theory, however, did not fully acquiesce to our hopes, leaving us only one relation between the thrust and jet mass sum distributions. Experimental tests of models proposing more extensive relations among these nonperturbative corrections seem to confirm our findings. This suggests a future di- rection of research to define new event shape variables, other than those standardly used in the past, which may receive universal nonperturbative corrections. This task was begun in perturbative QCD in Refs. [161, 162], and could be analyzed also in SCET. Similar methods could also be applied to other classes of events with QCD-jet backgrounds, or to the study of processes with collinear hadrons in the initial state, as occurs at any hadron collider.

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Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

Exploring whether there are additional Higgs bosons or exotic decay of the SM Higgs boson can give us direct evidences about physics beyond the Standard Model (BSM). Those include the two Higgs doublet models (2HDMs) [6–9], next-to-minimal superymmetric SM (NMSSM) [10, 11], composite Higgs models [12, 13], which favour the existence of other Higgs bosons in the high-mass regime, as well as lepton flavour violating (LFV) Higgs decay, three photons Higgs decay. There are strong evidences of dark matter from astrophysical observations which could be explained by the existence of weakly interacting massive particles (WIMPs, see Ref. [14] and the references therein). The observed Higgs boson might decay to dark matter or other stable or long-lived particles which do not interact significantly with a detector [15–19] leading to Higgs boson invisible decay.

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Beyond Standard Model Higgs boson physics with the ATLAS experiment at the LHC

Beyond Standard Model Higgs boson physics with the ATLAS experiment at the LHC

The recent observation of a new particle with mass 125–126 GeV at the LHC [1,2] opens a new era for particle physics. The detailed study of the production and decay modes of the new particle provides invaluable input to answer the question of whether this is indeed the long-sought Standard Model (SM) Higgs boson [3–8]. The first measurements indicate that the new particle is indeed compatible with the SM Higgs boson, see e.g., [9]. Nevertheless, many more measurements and data will be needed to extract reliable conclusions. This task is further complicated by the fact that many beyond SM physics scenarios include a SM-like Higgs boson, which is part of an extended scalar sector. In that case, searches for beyond SM Higgs bosons are very interesting, since they provide direct information on a possibly extended scalar sector, and hence they are complementary to the precise measurements of the properties of the new particle.

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Beyond the Standard Model Higgs Physics using the ATLAS Experiment

Beyond the Standard Model Higgs Physics using the ATLAS Experiment

The recent discovery of a Higgs boson with a mass of ap- proximately 125 GeV, and hence the mechanism respon- sible for electroweak symmetry breaking, represents a tri- umph of the physics program at the LHC [1, 2]. Current measurements on the properties of the discovered boson, such as its couplings, show consistency with those for a Higgs boson in the Standard Model (SM) [3]. However, further measurements and data are needed to show this conclusively. Even with such a SM-consistent Higgs bo- son, there are still issues within the SM - one example is the quantum corrections to the Higgs boson mass that have quadratic divergences. Possible extensions to the SM Higgs sector include adding a further Higgs doublet, col- lectively known as Two-Higgs-Doublet Models (2HDMs) [4]. A specific case of which, the Minimal Supersymmet- ric SM (MSSM) [5, 6], can solve these divergences.

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Neutrino mass implications for physics beyond the Standard Model

Neutrino mass implications for physics beyond the Standard Model

Precision studies of nuclear and neutron beta decay, which once played an important in the developments of the Standard Model, have been used to test the SM and look for the physics beyond it. Measurements of various correlation coe¢ cients provide constraints on the deviations from what the SM predicts. Several experiments have been carried out to measure the correlation coe¢ cients with improved precision. The abBA collaboration will make it possible to measure the correlations a; b; A; and B with precision of approximately 10 4 , using a pulsed cold neutron beam at the SNS in OAK Ridge. The WITCH (Weak Interaction Trap for CHarged particles) experiment[39] aims to measure the recoil energy spectrum of the daughter ions from -decay with a precision on a of about 0.5% or better. It will be used to search for both scalar and tensor weak interaction types.

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Prospects for Higgs Boson Measurements and Beyond Standard Model Physics at the High-Luminosity LHC with CMS

Prospects for Higgs Boson Measurements and Beyond Standard Model Physics at the High-Luminosity LHC with CMS

This paper presents physics studies and motivations that lead the development of the strategy of the future operation of the LHC collider with high luminosity (HL-LHC), also called LHC Phase-2. After the third long shutdown of the machine, that will take place around 2023, the instantaneous luminosity will be increased up to five times the design value, with 40 MHz operation (one bunch crossing every 25 ns) at a center of mass energy of 14 TeV. This yields challenging conditions for the CMS detector: up to 200 overlaying (pileup) events, high rates and high radiation levels, especially in the forward regions. An upgrade of the detectors is mandatory, in order to fully exploit the augmented luminosity and efficiently cope the new data taking conditions. It is foreseen that the total accumulated luminosity will reach 3000/fb of data, corresponding to ten times the data expected at the end of Phase- 1. This environment offers great opportunities to shade some light on some unexplored or not fully explored physics searches. Test of the Standard Model can be performed with su ffi cient precision in the Higgs sector, by accurately measuring the couplings to fermions and bosons. Searches for the associated production of two Higgs boson and measurement of the trilinear Higgs boson coupling can be a unique opportunity to test the Higgs potential and is sensitive to the presence of new physics that can be explored in both resonant and non-resonant searches. The measurement of the di ff erential cross-section of the Higgs boson is also an interesting test-bench of the Standard Model, providing that a percent precision can be reached.

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Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

In the Standard Model (SM), the mass of elementary particles is generated by the Brout-Englert-Higgs (BEH) mechanism [1–3] which implies the existence of a scalar field and associated scalar boson called the Higgs boson. In July 2012, the ATLAS and CMS experiments at the Large Hadron Collider announced the observation of a scalar particle with a mass of about 125 GeV and properties consistent with those of the Higgs boson predicted by the SM [4, 5]. This led to the 2013 Nobel prize being awarded to Higgs and Englert. While this discovery is tremendously important for the whole field, several problems in particle physics remain to be addressed, among them the unnatural fine-tuning of the Higgs mass, the grand unification problem, and the absence of candidates for dark matter. The proposed theories that aim at solving these problems often imply the presence of additional Higgs fields and / or Higgs boson couplings di ff erent from the SM ones.

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Baryon and Lepton Numbers in Particle Physics beyond the Standard Model

Baryon and Lepton Numbers in Particle Physics beyond the Standard Model

The last two chapters of this thesis were motivated by the second half of the tension mentioned earlier – the strict limits on the structure of new physics coming from mea- sured bounds on baryon and lepton number violating processes in laboratory experiments. These works focus on the possibility that these symmetries are not simply accidental global symmetries of the low energy theory, but rather relics of some more fundamental sponta- neously broken symmetry related to these numbers. In addition, the models are built into the minimal supersymmetric standard model (MSSM) in part because of the new gauge symmetries’ ability to replace R-parity, usually included in the MSSM to avoid dangerous B- and L-violating terms in the superpotential.

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The MoEDAL Experiment at the LHC - Searching for Physics Beyond the Standard Model

The MoEDAL Experiment at the LHC - Searching for Physics Beyond the Standard Model

The innovative MoEDAL detector employs unconventional methodologies tuned to the prospect of discovery physics. The largely passive MoEDAL detector has a dual nature. First, it acts like a giant camera, comprised of nuclear track detectors - analyzed offline by ultra fast scanning microscopes - sensitive only to new physics. Second, it is uniquely able to trap the particle messengers of physics beyond the Standard Model for further study. MoEDAL’s radiation environment is monitored by a state-of-the-art real-time TimePix pixel detector array. MoEDAL is currently installing a prototype of the MAPP (MoEDAL Apparatus for very Penetrating Particles) sub-detector, in a tunnel in the vicinity of LHCb / MoEDAL at IP8. This new subdetector is designed to search for very long-lived highly penetrating particles such a mini-charged particles, long lived neutrals, etc.

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Constraints on physics beyond the Standard Model and its observable effects

Constraints on physics beyond the Standard Model and its observable effects

While the value of studying particular new physics scenarios is evident, the rich- ness of possibilities for physics beyond the Standard Model indicates that model- independent analyses are also worthwhile. In this work, we will use both approaches. First, in Chapters 2 and 3 we will use general operator analyses to obtain model- independent constraints on the contributions of new physics to two processes—muon decay and Higgs production. (Interestingly, both of these processes can, in prin- ciple, receive contributions from new physics which also gives rise to the (not-yet- understood) phenomenon of neutrino mass.) Then, in Chapter 4, we will study a particular extra-dimensions model which attempts to address the cosmological con- stant problem. We discuss the motivation for each of these analyses below.

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Mass hierarchy and physics beyond the Standard Model

Mass hierarchy and physics beyond the Standard Model

Although extremely successful, the Standard Model or its supersymmetric version (MSSM) is not a fundamental theory, and this motivated the theoretical e ff orts to understand the nature of new physics beyond it. This search can be done using an e ff ective field theory approach, in which the “new physics” is parametrised by e ff ective operators. The power of this approach resides in arranging these operators in powers of 1/ M ∗ where M ∗ is the scale of new physics that generated them. To improve

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Geometry of the Standard Model of  Quantum Physics

Geometry of the Standard Model of Quantum Physics

All preceding attempts have supposed that the starting point was necessarily the standard model of quantum physics. The philosophical background of this choice is the believing in the necessity of the theoretical construc- tion made from quantum mechanics. This comes historically from the fact that the first wave equation, found by E. Schrödinger, was able to account not only for one particle, but for a lot of them. Unhappily this wave equa- tion is not relativistic. Consequently it is also unable to account for the spin 1/2, a common property for all fun- damental fermions of relativistic quantum physics.

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Search for new physics beyond the Standard Model in final states with jets and leptons+jets at CMS

Search for new physics beyond the Standard Model in final states with jets and leptons+jets at CMS

Abstract. Searches for new physics beyond the Standard Model performed by the CMS experiment in final states with jets and leptons+jets are presented. The document focuses on a selection of recent results from searches for heavy dijet resonances, leptoquarks, and heavy majorana neutrinos using proton-proton collision data at both √ s =8 and 13 TeV. The novel CMS datascouting technique, used to probe the low-mass region in hadronic final states, is introduced and results from a Run1 analysis are shown. Two searches in the electrons+jets final states showing an excess of events in Run1 data are also discussed.

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Topics in particle physics and cosmology beyond the standard model

Topics in particle physics and cosmology beyond the standard model

In the standard model of particle physics, the resolution of this problem is to make the mediators of the weak nuclear interaction gauge bosons, and then to break that gauge invariance spontaneously by introducing a scalar Higgs field with a non-zero VEV, thus giving the bosons the mass that accounts for the short range of the force they mediate. At high energies the gauge invariance is restored. The problematic longitudinal polarization disappears and is transmuted into the Goldstone boson of the spontaneously broken sym- metry. Since the Goldstone boson has no spin, it does not have the problem of a divergent rate of emission. This is the reason why many billions of dollars have been spent in the search for that yet-unseen Higgs boson, a search soon to come to a head with the turning on of the Large Hadron Collider (LHC) at CERN next year.

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Standard Model physics at ATLAS

Standard Model physics at ATLAS

The first measurement discussed here is dedicated to studies of jet internal substruc- ture [29]. Using √ s = 13 TeV data, measurements of several jet substructure observables for trimmed and soft drop jets, were performed. The full list of variables and the details about each can be found in the published paper [29]. Differential cross sections were measured and compared to MC generator predictions. As shown in Figure 13, the data is best described by Madgraph5+Pythia8, though none of the generator predictions is able to completely model the data.

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A Wave Equation including Leptons and Quarks for the Standard Model of Quantum Physics in Clifford Algebra

A Wave Equation including Leptons and Quarks for the Standard Model of Quantum Physics in Clifford Algebra

We have noticed, for the electron alone firstly (see [8] 2.4), next for electron + neutrino [2] the double link existing between the wave equation and the Lagrangian density: It is well known that the wave equation may be obtained from the Lagrangian density by the variational calculus. The new link is that the real part of the invariant wave equation is simply  = 0 . The Lagrangian formalism is then necessary, being a consequence of the wave equation. Next we have extended the double link to electro-weak interactions in the leptonic case (electron + neutrino). Now we are extending the double link to the gauge group of the standard model. The Lagrangian density must then be the real part of the invariant wave equation.

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Theory of 3 Folds 5 Dimensional Universe(Beyond Standard model of Particle Physics)

Theory of 3 Folds 5 Dimensional Universe(Beyond Standard model of Particle Physics)

The Large Hadron Collider at CERN announced results consistent with the Massive Higgs particle (God Particle, Spin=0) on July 4, 2012. Could this theory prove to be a last and thereby final truth? There are a number of important questions not answered by this theory, like: Constant Mass of Particles (Fermions), Matter-Antimatter Asymmetry, Nature of Particles related to 24% Gravitating Dark Matter & around 72% Repulsive Dark Energy, Union of Einstein’s Gravity Force (manifestation of the curvature of space and time; Continuous Nature of Space-Time) with Physical Forces (Particle Concept; Quanta Nature) like EMF, SNF & WNF of Standard Model, origin of 3 generations or families of Fermions viz. Quarks & Leptons etc.

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Physics in Discrete Spaces: On the Standard Model of Particles

Physics in Discrete Spaces: On the Standard Model of Particles

b) We have defined a so-called cosmic noise, a sort of temperature that describes the disorder of the most elementary physical systems (the cosmic bits) at a Planck scale. The cosmic noise, in our model, plays a central role in the organization and understanding of all natural phenomena. This noise could possibly be observed through phenomena relating to dark matter [3] or, perhaps, to the properties of quasars. The maps of dark matter would be, in reality, maps of cosmic noise.

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Standard Model and New physics for ε′k/εk

Standard Model and New physics for ε′k/εk

In order to predict ε ′ K in the SM, one has to calculate the hadronic matrix elements of four-quark operators with nonperturbative methods. The magenta bars in Fig. 1 have utilized analytic approaches to calculating them: chiral quark model (BEFL ’97), chiral perturbation theory (PPS ’01) with minimal hadronic approximation (HPR ’03), and the dual QCD approach (BG ’15). Note that the dual QCD approach predicts an upper bound on ε ′ K /ε K . Recently,

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A Quest for the Physics Beyond the Cosmological Standard Model

A Quest for the Physics Beyond the Cosmological Standard Model

In this paper we ask what happens when a cherished property of low-energy physics – rotational invariance – is violated during inflation. Rotational invariance is of course a subset of Lorentz invariance, and theoretical models of Lorentz violation in the current universe (and experimental constraints thereon) have been extensively studied in recent years [29, 30, 31, 32, 33]. Here we are specifically concerned with the possibility that rotational invariance may have been broken during inflation by an effect that has subsequently disappeared, and study the effects of such breaking on CMB anisotropies. It is possible that such an effect has already been detected, in the form of the “Axis of Evil,” an apparent alignment of the CMB multipoles on very large scales [34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54]. Although its statistical significance is hard to quantify, a variety of models have been put forward to explain this phenomenon [55, 56, 57, 58, 59, 60, 61, 62, 63, 64]. Our aim is not to construct a model contrived to explain the currently observed large-scale anomalies, but rather to make robust predictions for the observable consequences of a preferred direction during inflation, allowing observations to put constraints on its magnitude.

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