Large Spatial Dimensions Research Articles

Search for new physics in final states with an energetic jet or a hadronically decaying W or Z boson and transverse momentum imbalance at s=13 TeV

A search for new physics using events containing an imbalance in transverse momentum and one or more energetic jets arising from initial-state radiation or the hadronic decay of W or Z bosons is presented. A data sample of proton-proton collisions at $\sqrt{s} = $ 13 TeV, collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 35.9 fb$^{-1}$, is used. The observed data are found to be in agreement with the expectation from standard model processes. The results are interpreted as limits on the dark matter production cross section in simplified models with vector, axial-vector, scalar, and pseudoscalar mediators. Interpretations in the context of fermion portal and nonthermal dark matter models are also provided. In addition, the results are interpreted in terms of invisible decays of the Higgs boson and set stringent limits on the fundamental Planck scale in the Arkani-Hamed, Dimopoulos, and Dvali model with large extra spatial dimensions.

Search for new physics in events with a leptonically decaying Z boson and a large transverse momentum imbalance in proton\u2013proton collisions at sqrt{s} = 13,text {TeV}

A search for new physics in events with a Z boson produced in association with large missing transverse momentum at the LHC is presented. The search is based on the 2016 data sample of proton-proton collisions recorded with the CMS experiment at sqrt{s} = 13,text {TeV} , corresponding to an integrated luminosity of 35.9,text {fb}^{-1}. The results of this search are interpreted in terms of a simplified model of dark matter production via spin-0 or spin-1 mediators, a scenario with a standard-model-like Higgs boson produced in association with the Z boson and decaying invisibly, a model of unparticle production, and a model with large extra spatial dimensions. No significant deviations from the background expectations are found, and limits are set on relevant model parameters, significantly extending the results previously achieved in this channel.

Matter-antimatter asymmetry in the universe via string-inspired CPT violation at early eras

In four-space-time dimensional string/brane theory, obtained either through compactification of the extra spatial dimensions, or by appropriate restriction to brane worlds with three large spatial dimensions, the rich physics potential associated with the presence of non-trivial Kalb-Ramond (KR) axion-like fields has not been fully exploited so far. In this talk, I discuss a scenario whereby such fields produce spontaneous Lorentz- and CPT-violating cosmological backgrounds over which strings propagate, which in the early Universe can lead to Baryogenesis through Leptogenesis in models with heavy right-handed neutrinos.

Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy of 13 TeV collected in 2015 and 2016 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons (e or μ). Several signal regions are considered with increasing requirements on the missing transverse momentum above 250 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, and supersymmetric particles in several compressed scenarios.

Prospects for identification the direct and indirect effects of extra spatial dimensions at the Large Hadron Collider

The existence of massive graviton states, that may be produced as real and virtual particles in high-energy proton collisions, is predicted by the modern developments of Kaluza–Klein models with extra spatial dimensions. The direct and indirect signatures of large and warped extra spatial dimensions may be revealed by analyzing the specific characteristics of dilepton and diphoton final states formed in proton–proton collisions at the Large Hadron Collider (LHC). Virtual effects in the Kaluza–Klein models with large extra spatial dimensions can be discovered by the specic behavior of the dilpton and diphoton invariant-mass distributions, and their identication (in case of discovery) can be performed by the analysis of their angular distributions with integrated center-edge asymmetry. Assuming the nominal values of the LHC collision energy (14 TeV) and luminosity (100 fb–1), for the models with large extra spatial dimensions we find that the sensitivity to the cutoff parameter M S will extend up to 8.5 and 7.6 TeV for their discovery and identification, respectively. For the Randall–Sundrum model with a warped extra dimension, the LHC experiments will be sensitive to the graviton resonance with mass up to 4.4 and 3.1 TeV for its discovery and identification, respectively.

Remote Sensing, natural hazards and the contribution of ESA Sentinels missions

Natural hazards are phenomena with a large spatial dimension and impact. Their mapping and monitoring can be recorded only by using satellite remote image platforms. The range of the natural hazards and the way the latter affect the natural and manmade environments make the selection of the appropriate data types and analyses a challenging mission. Therefore, it is important that we understand the effects of each phenomenon as well as the potential relations between them, both in the temporal and spatial dimension. Furthermore, we take into account the availability and cost of the data in order to proceed to the selection of the appropriate data type and analysis as well as the potential of ESA's Sentinel missions. All in all, this paper aims at examining the recent technological developments ever since the advent of Remote Sensing via a variety of platforms and the latter's application for a better planning and confrontation of the natural hazards. Those which are of global interest and which occur more frequently during the last decades as a result of climate change are wild fires, flash floods in the urban and rural environments, landslides, tsunamis and soil erosion. Last but not least, the occurrence of volcanic activity, especially those in close proximity to urban areas, and heatwaves in the urban environment, are also mentioned.

Physics reach of MoEDAL at LHC: magnetic monopoles, supersymmetry and beyond

MoEDAL is a pioneering experiment designed to search for highly ionising messengers of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles, that are predicted to exist in a plethora of models beyond the Standard Model. Its ground-breaking physics program defines a number of scenarios that yield potentially revolutionary insights into such foundational questions as, are there extra dimensions or new symmetries, what is the mechanism for the generation of mass, does magnetic charge exist, what is the nature of dark matter, and, how did the big-bang develop at the earliest times. MoEDAL's purpose is to meet such far-reaching challenges at the frontier of the field. The physics reach of the existing MoEDAL detector is discussed, giving emphasis on searches for magnetic monopoles, supersymmetric (semi)stable partners, doubly charged Higgs bosons, and exotic structures such as black-hole remnants in models with large extra spatial dimensions and D-matter in some brane theories.

Effective string theory inspired potential and meson masses in higher dimension

Nambu–Goto action in classical bosonic string model for hadrons predicts quark-antiquark potential to be (Lüscher and Weisz. JHEP 07, 049 (2002). doi: 10.1088/1126-6708/2002/07/049 ) V(r) = −(γ/r) + σr + μ0. In this report we present studies of masses of heavy flavour mesons in higher dimension with our recently developed wave functions obtained following string inspired potential. We report the dimensional dependence of the masses of mesons. Our results suggest that as the meson mass increases with the number of extra spatial dimensions, it will attain the Planck scale (∼1019 GeV) asymptotically at an astronomically large spatial dimension (we call it Planck dimension) DPlanck ∼ 1011, which sets the limit of applicability of Schrodinger equation in large dimension.

Studying theρresonance parameters with staggered fermions

We deliver a lattice study of $\rho$ resonance parameters with p-wave $\pi\pi$ scattering phases, which are extracted by finite-size methods at one center-of-mass frame and four moving frames for six MILC lattice ensembles with pion masses ranging from $346$ to $ 176$ MeV. The effective range formula is applied to describe the scattering phases as a function of the energy covering the resonance region, this allows us to extract $\rho$ resonance parameters and to investigate the quark-mass dependence. Lattice studies with three flavors of the Asqtad-improved staggered fermions enable us to use the moving-wall source technique on large lattice spatial dimensions ($L=64$) and small light $u/d$ quarks. Numerical computations are carried out at two lattice spacings, $a \approx 0.12$ and $0.09$ fm.

Search for new phenomena in final states with an energetic jet and large missing transverse momentum inppcollisions ats=13 TeVusing the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton--proton collision data corresponding to an integrated luminosity of 3.2 fb${}^{-1}$ at $\sqrt{s}=13$ TeV collected in 2015 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons. Several signal regions are considered with increasing missing-transverse-momentum requirements between $E_{\rm T}^{\rm miss} >250$ GeV and $E_{\rm T}^{\rm miss} > 700$ GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with large extra spatial dimensions, pair production of weakly interacting dark-matter candidates, and the production of supersymmetric particles in several compressed scenarios.

Analysis of Mechanical Equipment Failure Based on Improved AFSA-SVM

Aiming at problems in detecting mechanic equipment failure like large spatial dimension of data and inaccurate failure effect, etc., this paper proposes a failure detection model (AFSA-SVM) combining artificial fish swarm algorithm (AFSA) and supporting vector machine. Firstly, encode subset of network features into location of artificial fish while taking detection rate of 50% cross verification SVM training model as the standard to evaluate the featured subset, and then find the optimal subset through simulating foraging, clustering and following behaviors of fish swarm. Finally, SVM detects failures according to the optimal featured subset, and show through specific experimental data that algorithm in this paper simplifies the neutral network structure and improves speed of detecting failures while guaranteeing the accuracy of detecting failures.

Nuclear shell model in natural basis

Shell model calculation is a key tool in investigating the nuclear structure. Traditional shell model calculations deal with the many-body correlations through the configurations interaction, in which one performs large-scale matrix diagonalization to study the excitation spectra for system in many basis states. The crucial starting point in shell model calculations is the derivative of effective interaction, which be either a microscopic approach based on realistic nuclear forces or a phenomenological determined interaction. Conventional shell model calculation always build the many-body wave functions in harmonic oscillator basis, which is always bound and localized. However, nuclei far from stability have strong coupling with the scattering states, low particle emission threshold and the wave functions have large spatial dimensions, which may lead the harmonic oscillator basis fail in describing the weakly bound nuclei.

Search for new phenomena in events with a photon and missing transverse momentum in pp collisions at s = 13 $$ \sqrt{s}=13 $$ TeV with the ATLAS detector

Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the Large Hadron Collider are reported. The data were collected in proton--proton collisions at a centre-of-mass energy of 13 TeV and correspond to an integrated luminosity of 3.2 $\rm fb^{-1}$. The observed data are in agreement with the Standard Model expectations. Exclusion limits are presented in models of new phenomena including pair production of dark matter candidates or large extra spatial dimensions. In a simplified model of dark matter and an axial-vector mediator, the search excludes mediator masses of up to 710 GeV for dark matter candidate masses up to 150 GeV. In an effective theory of dark matter production, values of the suppression scale $M_*$ up to 570 GeV are excluded and the effect of truncation for various coupling values is reported. For the ADD large extra spatial dimension model the search places more stringent limits than earlier searches in the same event topology, excluding $M_{\rm D}$ up to about 2.3 (2.8) TeV for two (six) additional spatial dimensions; the limits are reduced by 20--40% depending on the number of additional spatial dimensions when applying a truncation procedure.

Search for contact interactions and large extra dimensions in the dilepton final state using proton-proton collisions at [formula omitted] with the ATLAS detector

A search is conducted for non-resonant new phenomena in dielectron and dimuon final states, originating from either contact interactions (CI) or large extra dimensions (LED). The full LHC 2012 proton-proton collision dataset at s=8 TeV recorded by the ATLAS detector is used, corresponding to 20 fb-1. The invariant mass spectrum is used as a discriminating variable and for the first time in ATLAS CI searches, angular information is used to construct a forward-backward asymmetry to increase the search sensitivity. Lower limits are set on the CI scale Λ between 15.4 TeV and 26.3 TeV, and on the string scale MS for large extra spatial dimensions, from 3.2 TeV to 5.0 TeV. This 8 TeV result includes additional CI helicity models and LED formalism results to the 7 TeV ATLAS search.

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at [Formula: see text]TeV with the ATLAS detector.

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb{}^{-1} of sqrt{s}=8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with p_{mathrm {T}}> 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between E_{mathrm {T}}^{mathrm {miss}}>150 GeV and E_{mathrm {T}}^{mathrm {miss}}> 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presented.

Measures for a multidimensional multiverse

We explore the phenomenological implications of generalizing the causal patch and fat geodesic measures to a multidimensional multiverse, where the vacua can have differing numbers of large dimensions. We consider a simple model in which the vacua are nucleated from a $D$-dimensional parent spacetime through dynamical compactification of the extra dimensions, and compute the geometric contribution to the probability distribution of observations within the multiverse for each measure. We then study how the shape of this probability distribution depends on the time scales for the existence of observers, for vacuum domination, and for curvature domination (${t}_{\text{obs}},{t}_{\mathrm{\ensuremath{\Lambda}}}$, and ${t}_{c}$, respectively.) In this work we restrict ourselves to bubbles with positive cosmological constant, $\mathrm{\ensuremath{\Lambda}}$. We find that in the case of the causal patch cutoff, when the bubble universes have $p+1$ large spatial dimensions with $p\ensuremath{\ge}2$, the shape of the probability distribution is such that we obtain the coincidence of time scales ${t}_{\text{obs}}\ensuremath{\sim}{t}_{\mathrm{\ensuremath{\Lambda}}}\ensuremath{\sim}{t}_{c}$. Moreover, the size of the cosmological constant is related to the size of the landscape. However, the exact shape of the probability distribution is different in the case $p=2$, compared to $p\ensuremath{\ge}3$. In the case of the fat geodesic measure, the result is even more robust: the shape of the probability distribution is the same for all $p\ensuremath{\ge}2$, and we once again obtain the coincidence ${t}_{\text{obs}}\ensuremath{\sim}{t}_{\mathrm{\ensuremath{\Lambda}}}\ensuremath{\sim}{t}_{c}$. These results require only very mild conditions on the prior probability of the distribution of vacua in the landscape. Our work shows that the observed double coincidence of time scales is a robust prediction even when the multiverse is generalized to be multidimensional; that this coincidence is not a consequence of our particular Universe being ($3+1$)-dimensional; and that this observable cannot be used to preferentially select one measure over another in a multidimensional multiverse.

Search for new phenomena in events with a photon and missing transverse momentum inppcollisions ats=8 TeVwith the ATLAS detector

Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the LHC are reported. Data were collected in proton--proton collisions at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 20.3 fb$^{-1}$. The observed data are well described by the expected Standard Model backgrounds. The expected (observed) upper limit on the fiducial cross section for the production of such events is 6.1 (5.3) fb at 95% confidence level. Exclusion limits are presented on models of new phenomena with large extra spatial dimensions, supersymmetric quarks, and direct pair production of dark-matter candidates.

Search for contact interactions and large extra dimensions in the dilepton channel using proton-proton collisions at [Formula: see text]8TeV with the ATLAS detector.

A search is conducted for non-resonant new phenomena in dielectron and dimuon final states, originating from either contact interactions or large extra spatial dimensions. The LHC 2012 proton–proton collision dataset recorded by the ATLAS detector is used, corresponding to 20 fb^{-1} at sqrt{s} = 8 TeV. The dilepton invariant mass spectrum is a discriminating variable in both searches, with the contact interaction search additionally utilizing the dilepton forward-backward asymmetry. No significant deviations from the Standard Model expectation are observed. Lower limits are set on the ell ell q q contact interaction scale Lambda between 15.4 TeV and 26.3 TeV, at the 95 % credibility level. For large extra spatial dimensions, lower limits are set on the string scale M_mathrm{S} between 3.2 TeV to 5.0 TeV.

Gravity waves from cosmic bubble collisions

Our local Hubble volume might be contained within a bubble that nucleated in a false vacuum with only two large spatial dimensions. We study bubble collisions in this scenario and find that they generate gravity waves, which are made possible in this context by the reduced symmetry of the global geometry. These gravity waves would produce B-mode polarization in the cosmic microwave background, which could in principle dominate over the inflationary background.

Search for contact interactions and large extra dimensions in dilepton events fromppcollisions ats=7 TeVwith the ATLAS detector

A search for non-resonant new phenomena, originating from either contact interactions or large extra spatial dimensions, has been carried out using events with two isolated electrons or muons. These events, produced at the LHC in proton-proton collisions at sqrt(s) = 7 TeV, were recorded by the ATLAS detector. The data sample, collected throughout 2011, corresponds to an integrated luminosity of 4.9 and 5.0 fb-1 in the e+e- and mu+mu- channels, respectively. No significant deviations from the Standard Model expectation are observed. Using a Bayesian approach, 95% confidence limit lower limits ranging from 9.0 to 13.9 TeV are placed on the energy scale of llqq contact interactions in the left-left isoscalar model. Lower limits ranging from 2.4 to 3.9 TeV are also set on the string scale in large extra dimension models. After combination of these limits with results from a similar search in the diphoton channel, slightly more stringent limits are obtained.