Exotic Searches Research Articles

Exotics searches at ATLAS

Many theories beyond the Standard Model (SM) have been proposed to address several SM shortcomings, such as explaining why the Higgs boson is so light, the origin of neutrino masses, or the observed pattern of masses and mixing angles in the quark and lepton sectors. These beyond-the-SM extensions predict new particles or interactions directly accessible at the LHC. These proceedings will highlight recent searches based on the full Run 2 data collected by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV.

NICA prospects in searches for light exotics from hidden sectors: The cases of hidden photons and axion-like particles

We present first estimates of NICA sensitivity to Standard Model extensions with light hypothetical particles singlet under the known gauge transformations. Our analysis reveals that NICA can explore new regions in the parameter spaces of models with a hidden vector and models with an axion-like particle of masses about 30-500 MeV. Some of these regions seem unreachable by other ongoing and approved future projects. NICA has good prospects in discovery (5σ) of the new physics after 1 year of data taking.

Exotic Searches in CMS

Exotic Searches in CMS

The flavourful present and future of 2HDMs at the collider energy frontier

We study the intersection of flavour and collider physics for Two-Higgs-Doublet models of Type I and II. Drawing from the flavour precision-LHC exotics search complementarity, we also provide a projection of the future sensitivity that can be achieved in light of currently available analyses. On the one hand, we find that the parameter space of the 2HDM can be explored significantly further with more data from the LHC with some complementarity with flavour physics. On the other hand, flavour physics results alongside their projections remain powerful tools to constrain the model space in regions where direct sensitivity to new states via exotics searches is lost. Our results further high-light the recently observed flavour physics anomalies as important drivers of new physics searches in the future; we also touch on implications for a strong first order electroweak phase transition.

Effective connections of aμ , Higgs physics, and the collider frontier

We consider scalar extensions of the Standard Model (SM) and their effective field theoretic generalizations to illustrate the phenomenological connection between precision measurements of the anomalous magnetic moment of the muon ${a}_{\ensuremath{\mu}}$, precision Higgs measurements, and direct collider sensitivity. To this end, we consider charged beyond Standard Model (BSM) scalar sectors of the Zee-Babu type for which we develop a consistent and complete dimension-5 and -6 effective field theory extensions. This enables us to track generic new physics effects that interact with the SM predominantly via radiative interactions. While the operator space is high dimensional, the intersection of exotics searches at the Large Hadron Collider (LHC), Higgs signal strength, and anomalous muon magnetic measurements is manageably small. We find that consistency of LHC Higgs observations and ${a}_{\ensuremath{\mu}}$ requires a significant deformation of the new states' electroweak properties. Evidence in searches for doubly charged scalars as currently pursued by the LHC experiments can be used to further tension the BSMEFT parameter space and resolve blind directions in the effective field theory (EFT)-extended Zee-Babu scenario.

Exotic searches by ATLAS and CMS

ATLAS and CMS are two general-purpose detectors setting almost opposite to each other at the LHC ring. Both detectors resulted in the discovery of Higgs Boson in 2012. With successful data taking during Run-II, ATLAS and CMS recorded up to 139fb −1 of integrated luminosity and probes for rare and exotic decays and sets exclusion limits on various models searching beyond standard model physics.

JUNO detector: design and construction

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20-kton multi-purpose liquid scintillator detector currently being built in a dedicated underground laboratory located in the Jiangmen province (Southern China). JUNO' s main physics goal is the determination of the neutrino mass ordering using electron anti-neutrinos from two nuclear power plants at a baseline of about 53 km. This crucial measurement is supported by an unprecedented energy resolution of 3% at 1 MeV . Furthermore, the detector could observe supernova neutrinos, study atmospheric, solar and geo-neutrinos and perform exotic searches. Several challenges have been overcome during the construction of the largest liquid scintillator detector in the world, such as compatibility of the sphere material, mechanics of the stainless steel structure, scintillator light yield and transparency, PMTs detection efficiency. In this talk, JUNO's design as well as the status of its construction will be presented, together with a short excursion into its rich R&D program.

The Vanishing and Appearing Sources during a Century of Observations Project. I. USNO Objects Missing in Modern Sky Surveys and Follow-up Observations of a “Missing Star”

Abstract In this paper we report the current status of a new research program. The primary goal of the “Vanishing and Appearing Sources during a Century of Observations” project is to search for vanishing and appearing sources using existing survey data to find examples of exceptional astrophysical transients. The implications of finding such objects extend from traditional astrophysics fields to the more exotic searches for evidence of technologically advanced civilizations. In this first paper we present new, deeper observations of the tentative candidate discovered by Villarroel et al. in 2016. We then perform the first searches for vanishing objects throughout the sky by comparing 600 million objects from the US Naval Observatory Catalogue (USNO) B1.0 down to a limiting magnitude of ∼20–21 with the recent Pan-STARRS Data Release-1 (DR1) with a limiting magnitude of ∼23.4. We find about 150,000 preliminary candidates that do not have any Pan-STARRS counterpart within a 30″ radius. We show that these objects are redder and have larger proper motions than typical USNO objects. We visually examine the images for a subset of about 24,000 candidates, superseding the 2016 study with a sample 10 times larger. We find about 100 point sources visible in only one epoch in the red band of the USNO, which may be of interest in searches for strong M-dwarf flares, high-redshift supernovae, or other categories of unidentified red transients.

Exotic searches with the ATLAS detector

The summary is given for the exotic, non-SUSY searches for new physics with the ATLAS detector at Large Hadron Collider(LHC). The results presented use data collected at center-of-mass energies of , for data sets corresponding to a variety of integrated luminosities. Searches using leptons, photons, missing transverse energy, and jets are performed, as well as searches requiring custom jet and track reconstruction, and searches for so-called lepton jets. No deviations from Standard Model expectations are observed, hence constraints are placed on the phase space of available theoretical models.

Search for exotics at NA62

Fixed target experiments are a particularly useful tool in the search of very weakly coupled particles in the MeV-GeV range, which are of interest as potential dark matter mediators. Owing to the high beam energy and a hermetic detector coverage, NA62 also has the opportunity to directly search for a variety of long-lived beyond the Standard Model particles, such as axion-like particles and dark photons. Furthermore, the large sample of K+ decays available at NA62 allows a rich program for rare and forbidden decay studies. In this paper the status of these searches is reviewed, giving prospects for future data taking at NA62.

Exotic searches at NA62

The NA62 Experiment, thanks to the high intensity proton beam provided by the SPS, is a suitable apparatus to search for Beyond Standard Model (BSM) scenarios feebly coupled to SM, manifesting itself at the MeV-GeV energy range. In this document a report of Heavy Neutral Lepton and Dark Photons searches results and the prospect for other BSM searches at NA62 are given.

X, Y, Z Search at Belle II

Search for exotics has increased importance since the observation of the X(3872), 13 years ago, announced by the Belle Collaboration. The observation of pentaquark states by LHCb, and the Z-charged states observed at Belle and BES III have raised even more the attention to the field. Presently several states are observed that do not fit potential models, and looking for them in different production mechanisms and search for their decay modes it is important, as well as to do precise measurement of their mass, width, lineshape. We shortly report in this note about the plan in searching for exotics at Belle II at KEK (Tsukuba, Japan), that just ended the Phase-II running period, and show the first re-discovery results using 5 pb−1 integrated luminosity.

Long-lived staus and displaced leptons at the LHC

As the majority of LHC searches are focused on prompt signatures, specific long-lived particles have the potential to be overlooked by the otherwise systematic new physics programs at ATLAS and CMS. While in many cases long-lived superparticles are now stringently constrained by existing exotic searches, we point out that the highly motivated model of gauge mediation with staus as the next-to-lightest superparticle (NLSP) has received less attention. We recast LHC searches for heavy stable charged particles, disappearing tracks, and opposite-flavor leptons with large impact parameters to assess current constraints on a variety of spectra that contain an NLSP stau, and find that portions of the parameter space motivated by naturalness are still experimentally unexplored. We additionally note a gap in the current experimental search program: same-flavor leptons with large impact parameters evade the suite of existing searches for long-lived objects. This gap is especially noteworthy as vetoes on displaced leptons in prompt new physics searches could be systematically discarding such events. We discuss several motivated models that can exhibit same-flavor displaced leptons: gauge mediation with co-NLSP sleptons, extended gauge mediation, R-parity violation, and lepton-flavored dark matter that freezes in during a matter-dominated era of the early universe. To address this gap, we propose a straightforward extension of the CMS search for leptons with large impact parameters, and project sensitivity to these scenarios at 13 TeV. Throughout this analysis, we highlight several methods whereby LHC searches for exotic long-lived objects could potentially improve their sensitivity to the displaced leptons originating from gauge mediation and beyond.

Combination of Run-1 exotic searches in diboson final states at the LHC

We perform a statistical combination of the ATLAS and CMS results for the search of a heavy resonance decaying to a pair of vector bosons with the $\sqrt{s}=8$ TeV datasets collected at the LHC. We take into account six searches in hadronic and semileptonic final states carried out by the two collaborations. We consider only public information provided by ATLAS and CMS in the HEPDATA database and in papers published in refereed journals. We interpret the combined results within the context of a few benchmark new physics models, such as models predicting the existence of a {\ensuremath{\mathrm{W^\prime}}\xspace} or a bulk Randall-Sundrum spin--2 resonance, for which we present exclusion limits, significances, $p$-values and best-fit cross sections. A heavy diboson resonance with a production cross section of $\sim$4-5 fb and mass between 1.9 and 2.0 TeV is the exotic scenario most consistent with the experimental results. Models in which a heavy resonance decays preferentially to a WW final state are disfavoured.

Precision tests of the Standard Model with Kaon decays at CERN

Effects of new physics in flavor could be found both in Flavor Changing Neutral Current (FCNC) processes and in Lepton Flavor Violation (LFV) modes. The former offer the possibility to deeply test the standard model in a clean environment, while the latter are sensitive to contribution from several models beyond the standard model. In the Kaon sector both FCNC and LFV will be investigated in the NA62 experiment. In addition the kaons sector is an ideal place where to look for new particles and tiny effects, in the region of hundreds of MeV/c2. In this paper prospects for exotic searches in NA62 will be presented, together with recent results from NA48/2 and NA62-RK on LFV kaon decays modes.

Exotics Searches at ATLAS

Exotics Searches at ATLAS

Testing ATLAS diboson excess with dark matter searches at LHC

The ATLAS collaboration has recently reported a 2.6 sigma excess in the search for a heavy resonance decaying into a pair of weak gauge bosons. Only fully hadronic final states are being looked for in the analysis. If the observed excess really originates from the gauge bosons' decays, other decay modes of the gauge bosons would inevitably leave a trace on other exotic searches. In this paper, we propose the use of the Z boson decay into a pair of neutrinos to test the excess. This decay leads to a very large missing energy and can be probed with conventional dark matter searches at the LHC. We discuss the current constraints from the dark matter searches and the prospects. We find that optimizing these searches may give a very robust probe of the resonance, even with the currently available data of the 8 TeV LHC.

Jiangmen Underground Neutrino Observatory

The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose neutrino-oscillation experiment designed to determine the neutrino mass hierarchy and to precisely measure oscillation parameters by detecting reactor antineutrinos, observe supernova neutrinos, study the atmospheric, solar neutrinos and geo-neutrinos, and perform exotic searches, with a 20 kiloton liquid scintillator detector of unprecedented 3% energy resolution (at 1 MeV) at 700-meter deep underground and to have other rich scientific possibilities. Currently MC study shows a sensitivity of the mass hierarchy to be Δχ2‾∼11 and Δχ2‾∼16 in a relative and an absolute measurement, respectively. JUNO has been approved by Chinese Academy of Sciences in 2013, and an international collaboration was established in 2014. The civil construction is in preparation and the R&D of the detectors are ongoing. A new offline software framework was developed for the detector simulation, the event reconstruction and the physics analysis. JUNO is planning to start taking data around 2020.

The P̄ANDA Experiment

The PANDA (anti-Proton ANnihiliation at DArmstadt) experiment will be a multipurpose apparatus at the future Facility for Antiproton and Ion Research (FAIR) at Darmstadt. Anti-proton induced reactions with 1.5 to 15 GeV/c beam momentum at high luminosities of up to 2•1032/(s•cm2) will be investigated. Exclusive detection of whole events with almost 4π acceptance and high precision are needed for the broad physics program. The focus lies on studying the strong interaction in the charm region, by charmonium, open-charm and baryon spectroscopy, and includes the search for glueballs, hybrids and other exotics, hypernuclear physics, nucleon structure studies as well as in-medium modifications of hadrons.

Double-Regge exchange limit for theγp→K+K−preaction

We apply the generalized Veneziano model ($B_5$ model) in the double-Regge exchange limit to the $\gamma p \to K^+ K^- p$ reaction. Four different cases defined by the possible combinations of the signature factors of leading Regge exchanges (($K^*,a_2/f_2$), ($K^*,\rho/\omega$), ($K_2^*,a_2/f_2$), and ($K_2^*,\rho/\omega$)) have been simulated through the Monte Carlo method. Suitable event candidates for the double-Regge exchange high-energy limit were selected employing \textit{Van Hove} plots as a better alternative to kinematical cuts in the $K^+ K^- p$ Dalitz plot. In this way we predict and analyze the double-Regge contribution to the $K^+ K^- p$ Dalitz plot, which constitutes one of the major backgrounds in the search for strangeonia, hybrids and exotics using $\gamma p\rightarrow K^+K^-p$ reaction. We expect that data currently under analysis, and that to come in the future, will allow verification of the double-Regge behavior and a better assessment of this component of the amplitude.