A general search for new phenomena in ep scattering at HERA

Aktas, A.; Andreev, V.; Anthonis, T.; Asmone, A.; Babaev, A.; Backović, S.; Bähr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Böhme, J.; Boenig, M.-O.; Boudry, V.; Braciník, J.; Brisson, V.; Bröker, H.-B.; Brown, D.; Bruncko, D.; Büsser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.; Caron, S.; Cassol-Brunner, F.; C̆erný, K.; Chekelian, V.; Contreras, J. G.; Coppens, Y.R.; Coughlan, J. A.; Cox, B.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; Roeck, A. De; Desch, K.; Wolf, E. A. De; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, Peter; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flügge, G.; Fomenko, A.; Foresti, I.; Formánek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grässler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, G.; Gwilliam, C. B.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, Magnus; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Heuer, R. D.; Hildebrandt, M.; Hiller, K. H.; Höting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismaïl, Mohamed; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, Martin; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Krüger, K.; Kückens, J.; Kuhr, T.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laycock, P.; Lebedev, A.; Leißner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; López-Fernández, R.; Lubimov, V.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martišíková, M.; Martyn, H. U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, Andreas Bernhard; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J. V.; Mozer, M. U.; Müller, K.; Мурін, П.; Nagovizin, V.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nožička, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Ossoskov, G.; Ozerov, D.; Paramonov, A.; Pascaud, C.; Patel, G. D.; Peez, M.; Pérez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Pöschl, R.; Portheault, B.; Povh, Bogdan; Raičević, N.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S. V.; Rybicki, K.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schöning, A.; Schröder, V.; Schultz‐Coulon, H.‐C.; Schwanenberger, C.; Sedlák, Kamil; Sefkow, F.; Sheviakov, I.; Shtarkov, L. N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, Peter; Tomasz, F.; Traynor, D.; Truöl, P.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, M.; Usik, A.; Utkin, D.; Valkár, Š.; Valkárová, A.; Vallée, C.; Mechelen, P. Van; Remortel, N. Van; Trevino, A. Vargas; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G. G.; Wissing, C.; Woehrling, E.-E.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W. G.; Yeganov, V.; Žáček, J.; Zálešâk, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

doi:10.1016/j.physletb.2004.09.057

Cited by 58 publications

(62 citation statements)

References 29 publications

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“…• A series of signal model agnostic, but background model-dependent searches have been performed by D0 [10][11][12][13], H1 [14,15], CDF [16][17][18], CMS [19,20], and ATLAS [21][22][23]. All of these searches share essentially the same approach: they compared histograms of data to histograms of SM simulations and looked for discrepancies.…”

Section: Bsm Sensitivitymentioning

confidence: 99%

Anomaly detection with density estimation

2020

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We leverage recent breakthroughs in neural density estimation to propose a new unsupervised anomaly detection technique (ANODE). By estimating the probability density of the data in a signal region and in sidebands, and interpolating the latter into the signal region, a likelihood ratio of data vs. background can be constructed. This likelihood ratio is broadly sensitive to overdensities in the data that could be due to localized anomalies. In addition, a unique potential benefit of the ANODE method is that the background can be directly estimated using the learned densities. Finally, ANODE is robust against systematic differences between signal region and sidebands, giving it broader applicability than other methods. We demonstrate the power of this new approach using the LHC Olympics 2020 R&D Dataset. We show how ANODE can enhance the significance of a dijet bump hunt by up to a factor of 7 with a 10% accuracy on the background prediction. While the LHC is used as the recurring example, the methods developed here have a much broader applicability to anomaly detection in physics and beyond.

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Section: Bsm Sensitivitymentioning

confidence: 99%

Anomaly detection with density estimation

2020

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“…The analysis is performed by the H1 Collaboration using their complete e ± p data set [228], corresponding to an integrated luminosity of 463 pb −1 , of which 178 pb −1 was recorded in e − p collisions and 285 pb −1 in e + p collisions. Following the analysis strategy of a previous H1 publication which used only the HERA I data set [229], a search for differences between the observed number of data events and the SM expectation in a large variety of different event topologies is performed. The analysis includes all high P T final state topologies involving electrons (e), muons (µ), jets (j), photons (γ) or neutrinos (ν) and searches for deviations from the SM prediction in phase-space regions where the SM predictions are reliable.…”

Section: A General Search For New Phenomenamentioning

confidence: 99%

“…Inclusive CC DIS events are simulated using DJANGOH. The leading order MC prediction of processes with two or more high transverse momentum jets in NC DIS, CC DIS and photoproduction is scaled by a factor of 1.2 to account for the incomplete description of higher orders in the MC generators [264,229]. Additional, smaller contributions from single W boson production and lepton pair production are modelled using EPVEC and GRAPE, respectively.…”

Section: Search For Squarks In R-parity Violating Supersymmetrymentioning

confidence: 99%

Review of searches for rare processes and physics beyond the Standard Model at HERA

South

Turcato

2016

Eur. Phys. J. C

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The electron-proton collisions collected by the H1 and ZEUS experiments at HERA comprise a unique particle physics data set, and a comprehensive range of measurements has been performed to provide new insight into the structure of the proton. The high centre of mass energy at HERA has also allowed rare processes to be studied, including the production of W and Z 0 bosons and events with multiple leptons in the final state. The data have also opened up a new domain to searches for physics beyond the Standard Model including contact interactions, leptoquarks, excited fermions and a number of supersymmetric models. This review presents a summary of such results, where the analyses reported correspond to an integrated luminosity of up to 1 fb −1 , representing the complete data set recorded by the H1 and ZEUS experiments.

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“…The distribution of the fluctuations were consistent with statistical expectations. This methodology was eventually adopted by other experiments, for example at the HERA experiments, 143 and the CDF experiment in Run II where it was extended for the other types of systematic, model-independent search strategies (described in section 5.4). This methodology is currently less used for a number of reasons, primarily that it is not always clear how to quantify the search sensitivity to new physics.…”

Section: Signature-based Searches and Sleuthmentioning

confidence: 99%

Review of physics results from the Tevatron: Searches for new particles and interactions

Toback

Živković

2015

Int. J. Mod. Phys. A

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We present a summary of results for searches for new particles and interactions at the Fermilab Tevatron collider by the CDF and the D0 experiments. These include results from Run I as well as Run II for the time period up to July 2014. We focus on searches for supersymmetry, as well as other models of new physics such as new fermions and bosons, various models of excited fermions, leptoquarks, technicolor, hidden-valley model particles, long-lived particles, extra dimensions, dark matter particles, and signaturebased searches. a Note that for simplicity, when we say we are looking for a model, like SUSY, we are looking for evidence of new particles and/or interactions. September 18, 2014 0:22 NP˙review˙v3 4 D. Toback, L.Živkovićissues, like production mechanisms, decay products, final states and relevant models parameters are discussed in sections 4 and 5. SupersymmetryThe motivations for SUSY are well known and documented 4-7 and include its ability to potentially solve hierarchy problem for the Higgs boson mass, provide a dark matter candidate, and satisfy consistency requirements of modern models of string theory. Inherent in the theory is that for every fermion observed in the SM there is a supersymmetric boson partner that has not yet been observed; the same is true for the known bosons, including the observed Higgs boson, and the hypothetical graviton (the particle mediator of gravity). The non-observation of low-mass sparticles with equal masses to their SM counterparts has focused efforts on SUSY models with broken symmetry.Since there are many new particles to be searched for, and a 128 free parameters in the most general models, other "clues" and possible tie-ins have been used by model builders to focus on weak-scale SUSY. 8 The hallmark of these SUSY models is their ability to provide a dark matter candidate, and not contradict other observations. 9 Since experimental results from the proton and electron lifetime measurements imply conservation of baryon number and lepton number, it is not unreasonable that SUSY has an additional symmetry, known as R-parity b . If R-parity is conserved this has the consequence that the lightest SUSY particle (LSP) must be stable, potentially making it a dark matter candidate. We note for now that for many SUSY models the LSP couple to normal matter with a tiny strength and when produced in a collision, it would leave the detector without a trace, yielding significant missing transverse energy, E T , giving a signature for SUSY that is searched for in many models.With this in mind we quickly mention the models focused on at the Fermilab Tevatron collider which are typically selected for simplicity and general features. These include: (i) gravity-mediated SUSY breaking (minimal SuperGravity or mSUGRA) type models, where the lightest neutralino is the LSP, has a mass at the electroweak scale and becomes a natural cold-dark matter candidate (discussed in section 4.1), (ii) gauge-mediated SUSY breaking models (GMSB) which have a ∼keV mass gravitino as the LSP, and often h...

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A general search for new phenomena in ep scattering at HERA

Cited by 58 publications

References 29 publications

Anomaly detection with density estimation

Anomaly detection with density estimation

Review of searches for rare processes and physics beyond the Standard Model at HERA

Review of physics results from the Tevatron: Searches for new particles and interactions

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