Search for top-quark partners with charge 5/3 in the same-sign dilepton final state

A search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5 fb(-1) and was collected at sqrt[s] = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected background, and the existence of top-quark partners with masses below 800 GeV is excluded at a 95% confidence level, assuming they decay exclusively to tW. This is the first limit on these particles from the LHC, and it is significantly more restrictive than previous limits.

Search for flavor-changing neutral currents in top-quark decays t → Zq in pp collisions at sqrt[s] = 8 TeV

A search for flavor-changing neutral currents in top-quark decays t → Zq is performed in events produced from the decay chain tt → Zq+Wb, where both vector bosons decay leptonically, producing a final state with three leptons (electrons or muons). A data set collected with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 19.7 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV. No excess is seen in the observed number of events relative to the standard model prediction; thus, no evidence for flavor-changing neutral currents in top-quark decays is found. A combination with a previous search at 7 TeV excludes a t → Zq branching fraction greater than 0.05% at the 95% confidence level.

The effects of a xanthan gum-based thickener on the swallowing function of patients with dysphagia

BACKGROUND

Increasing bolus viscosity of thin liquids is a basic therapeutic strategy to protect patients with oropharyngeal dysphagia (OD) from aspiration. However, conventional starch thickeners increase post-deglutitive residue.

AIM

To assess the therapeutic effect of a new xanthan gum-based thickener, Resource ThickenUp Clear (Nestlé Health Science, Vevey, Switzerland) on patients with oropharyngeal dysphagia.

METHODS

We studied the effect of Resource ThickenUp Clear using a clinical method and videofluoroscopy on 120 patients with oropharyngeal dysphagia (66 with stroke, 41 older and 13 with neurodegenerative diseases) and 14 healthy volunteers while swallowing thin-liquid, nectar-like and spoon-thick boluses. We assessed the prevalence of signs of impaired safety and efficacy of swallow and the physiology of the swallow response.

RESULTS

Increasing bolus viscosity with Resource ThickenUp Clear: (i) improved safety of swallow demonstrated by a reduction in the prevalence of cough and voice changes in the clinical study and penetrations and aspirations during video fluoroscopy. Prevalence of aspirations was 12.7% with thin liquid, 7.7% with nectar-like (P < 0.01) and 3.4% with spoon-thick (P < 0.01) viscosities. Penetration-Aspiration Scale was reduced from 3.24 ± 0.18 at thin liquid to 2.20 ± 0.18 at nectar-like (P < 0.001) and to 1.53 ± 0.13 at spoon-thick (P < 0.001) viscosities; (ii) did not enhance pharyngeal residue; (iii) nectar-like viscosity did not affect bolus velocity nor timing of swallow response and (iv) spoon-thick viscosity reduced bolus velocity.

CONCLUSIONS

Resource ThickenUp Clear improves the safety of swallow without increasing residue providing a viscosity-dependent therapeutic effect for patients with oropharyngeal dysphagia. At nectar viscosity, the effect is due to intrinsic texture properties, spoon-thick viscosity adding changes in swallow physiology. NCT01158313.

Search for top squark and Higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top quark (the top squark) and the Higgs boson (Higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7  fb-1 of proton-proton collision data at s=8  TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the top squark mass below 360 to 410 GeV, depending on the Higgsino mass.

John J, Sulak L, Alimena J, Bhattacharya S, Christopher G, Cutts D, Demiragli Z, Ferapontov A, Garabedian A, Heintz U, Jabeen S, Kukartsev G, Laird E, Landsberg G, Luk M, Narain M, Segala M, Sinthuprasith T, Speer T, Breedon R, Breto G, Calderon De La Barca Sanchez M, Chauhan S, Chertok M, Conway J, Conway R, Cox PT, Erbacher R, Gardner M, Houtz R, Ko W, Kopecky A, Lander R, Mall O, Miceli T, Nelson R, Pellett D, Ricci-Tam F, Rutherford B, Searle M, Smith J, Squires M, Tripathi M, Wilbur S, Yohay R, Andreev V, Cline D, Cousins R, Erhan S, Everaerts P, Farrell C, Felcini M, Hauser J, Ignatenko M, Jarvis C, Rakness G, Schlein P, Takasugi E, Traczyk P, Valuev V, Weber M, Babb J, Clare R, Dinardo ME, Ellison J, Gary JW, Hanson G, Liu H, Long OR, Luthra A, Nguyen H, Paramesvaran S, Sturdy J, Sumowidagdo S, Wilken R, Wimpenny S, Andrews W, Branson JG, Cerati GB, Cittolin S, Evans D, Holzner A, Kelley R, Lebourgeois M, Letts J, Macneill I, Mangano B, Padhi S, Palmer C, Petrucciani G, Pieri M, Sani M, Sharma V, Simon S, Sudano E, Tadel M, Tu Y, Vartak A, Wasserbaech S, Würthwein F, Yagil A, Yoo J, Barge D, Bellan R, Campagnari C, D’Alfonso M, Danielson T, Flowers K, Geffert P, George C, Golf F, Incandela J, Justus C, Kalavase P, Kovalskyi D, Krutelyov V, Lowette S, naVillalba RM, Mccoll N, Pavlunin V, Ribnik J, Richman J, Rossin R, Stuart D, To W, West C, Apresyan A, Bornheim A, Bunn J, Chen Y, Di Marco E, Duarte J, Kcira D, Ma Y, Mott A, Newman HB, Rogan C, Spiropulu M, Timciuc V, Veverka J, Wilkinson R, Xie S, Yang Y, Zhu RY, Azzolini V, Calamba A, Carroll R, Ferguson T, Iiyama Y, Jang DW, Liu YF, Paulini M, Russ J, Vogel H, Vorobiev I, Cumalat JP, Drell BR, Ford WT, Gaz A, Luiggi Lopez E, Nauenberg U, Smith JG, Stenson K, Ulmer KA, Wagner SR, Alexander J, Chatterjee A, Eggert N, Gibbons LK, Hopkins W, Khukhunaishvili A, Kreis B, Mirman N, Nicolas Kaufman G, Patterson JR, Ryd A, Salvati E, Sun W, Teo WD, Thom J, Thompson J, Tucker J, Weng Y, Winstrom L, Wittich P, Winn D, Abdullin S, Albrow M, Anderson J, Apollinari G, Bauerdick LAT, Beretvas A, Berryhill J, Bhat PC, Burkett K, Butler JN, Chetluru V, Cheung HWK, Chlebana F, Cihangir S, Elvira VD, Fisk I, Freeman J, Gao Y, Gottschalk E, Gray L, Green D, Gutsche O, Hare D, Harris RM, Hirschauer J, Hooberman B, Jindariani S, Johnson M, Joshi U, Klima B, Kunori S, Kwan S, Leonidopoulos C, Linacre J, Lincoln D, Lipton R, Lykken J, Maeshima K, Marraffino JM, Martinez Outschoorn VI, Maruyama S, Mason D, McBride P, Mishra K, Mrenna S, Musienko Y, Newman-Holmes C, O’Dell V, Prokofyev O, Ratnikova N, Sexton-Kennedy E, Sharma S, Spalding WJ, Spiegel L, Taylor L, Tkaczyk S, Tran NV, Uplegger L, Vaandering EW, Vidal R, Whitmore J, Wu W, Yang F, Yun JC, Acosta D, Avery P, Bourilkov D, Chen M, Cheng T, Das S, De Gruttola M, Di Giovanni GP, Dobur D, Drozdetskiy A, Field RD, Fisher M, Fu Y, Furic IK, Hugon J, Kim B, Konigsberg J, Korytov A, Kropivnitskaya A, Kypreos T, Low JF, Matchev K, Milenovic P, Mitselmakher G, Muniz L, Remington R, Rinkevicius A, Skhirtladze N, Snowball M, Yelton J, Zakaria M, Gaultney V, Hewamanage S, Lebolo LM, Linn S, Markowitz P, Martinez G, Rodriguez JL, Adams T, Askew A, Bochenek J, Chen J, Diamond B, Gleyzer SV, Haas J, Hagopian S, Hagopian V, Johnson KF, Prosper H, Veeraraghavan V, Weinberg M, Baarmand MM, Dorney B, Hohlmann M, Kalakhety H, Yumiceva F, Adams MR, Apanasevich L, Bazterra VE, Betts RR, Bucinskaite I, Callner J, Cavanaugh R, Evdokimov O, Gauthier L, Gerber CE, Hofman DJ, Khalatyan S, Kurt P, Lacroix F, Moon DH, O’Brien C, Silkworth C, Strom D, Turner P, Varelas N, Akgun U, Albayrak EA, Bilki B, Clarida W, Dilsiz K, Duru F, Griffiths S, Merlo JP, Mermerkaya H, Mestvirishvili A, Moeller A, Nachtman J, Newsom CR, Ogul H, Onel Y, Ozok F, Sen S, Tan P, Tiras E, Wetzel J, Yetkin T, Yi K, Barnett BA, Blumenfeld B, Bolognesi S, Fehling D, Giurgiu G, Gritsan AV, Guo ZJ, Hu G, Maksimovic P, Swartz M, Whitbeck A, Baringer P, Bean A, Benelli G, Kenny III RP, Murray M, Noonan D, Sanders S, Stringer R, Wood JS, Barfuss AF, Chakaberia I, Ivanov A, Khalil S, Makouski M, Maravin Y, Shrestha S, Svintradze I, Gronberg J, Lange D, Rebassoo F, Wright D, Baden A, Calvert B, Eno SC, Gomez JA, Hadley NJ, Kellogg RG, Kolberg T, Lu Y, Marionneau M, Mignerey AC, Pedro K, Peterman A, Skuja A, Temple J, Tonjes MB, Tonwar SC, Apyan A, Bauer G, Busza W, Butz E, Cali IA, Chan M, Dutta V, Gomez Ceballos G, Goncharov M, Kim Y, Klute M, Lai YS, Levin A, Luckey PD, Ma T, Nahn S, Paus C, Ralph D, Roland C, Roland G, Stephans GSF, Stöckli F, Sumorok K, Sung K, Velicanu D, Wolf R, Wyslouch B, Yang M, Yilmaz Y, Yoon AS, Zanetti M, Zhukova V, Dahmes B, De Benedetti A, Franzoni G, Gude A, Haupt J, Kao SC, Klapoetke K, Kubota Y, Mans J, Pastika N, Rusack R, Sasseville M, Singovsky A, Tambe N, Turkewitz J, Cremaldi LM, Kroeger R, Perera L, Rahmat R, Sanders DA, Summers D, Avdeeva E, Bloom K, Bose S, Claes DR, Dominguez A, Eads M, Gonzalez Suarez R, Keller J, Kravchenko I, Lazo-Flores J, Malik S, Meier F, Snow GR, Dolen J, Godshalk A, Iashvili I, Jain S, Kharchilava A, Kumar A, Rappoccio S, Wan Z, Alverson G, Barberis E, Baumgartel D, Chasco M, Haley J, Massironi A, Nash D, Orimoto T, Trocino D, Wood D, Zhang J, Anastassov A, Hahn KA, Kubik A, Lusito L, Mucia N, Odell N, Pollack B, Pozdnyakov A, Schmitt M, Stoynev S, Velasco M, Won S, Berry D, Brinkerhoff A, Chan KM, Hildreth M, Jessop C, Karmgard DJ, Kolb J, Lannon K, Luo W, Lynch S, Marinelli N, Morse DM, Pearson T, Planer M, Ruchti R, Slaunwhite J, Valls N, Wayne M, Wolf M, Antonelli L, Bylsma B, Durkin LS, Hill C, Hughes R, Kotov K, Ling TY, Puigh D, Rodenburg M, Smith G, Vuosalo C, Williams G, Winer BL, Wolfe H, Berry E, Elmer P, Halyo V, Hebda P, Hegeman J, Hunt A, Jindal P, Koay SA, Lopes Pegna D, Lujan P, Marlow D, Medvedeva T, Mooney M, Olsen J, Piroué P, Quan X, Raval A, Saka H, Stickland D, Tully C, Werner JS, Zenz SC, Zuranski A, Brownson E, Lopez A, Mendez H, Ramirez Vargas JE, Alagoz E, Benedetti D, Bolla G, Bortoletto D, De Mattia M, Everett A, Hu Z, Jones M, Jung K, Koybasi O, Kress M, Leonardo N, Maroussov V, Merkel P, Miller DH, Neumeister N, Shipsey I, Silvers D, Svyatkovskiy A, Vidal Marono M, Wang F, Xu L, Yoo HD, Zablocki J, Zheng Y, Guragain S, Parashar N, Adair A, Akgun B, Ecklund KM, Geurts FJM, Li W, Padley BP, Redjimi R, Roberts J, Zabel J, Betchart B, Bodek A, Covarelli R, De Barbaro P, Demina R, Eshaq Y, Ferbel T, Garcia-Bellido A, Goldenzweig P, Han J, Harel A, Miner DC, Petrillo G, Vishnevskiy D, Zielinski M, Bhatti A, Ciesielski R, Demortier L, Goulianos K, Lungu G, Malik S, Mesropian C, Arora S, Barker A, Chou JP, Contreras-Campana C, Contreras-Campana E, Duggan D, Ferencek D, Gershtein Y, Gray R, Halkiadakis E, Hidas D, Lath A, Panwalkar S, Park M, Patel R, Rekovic V, Robles J, Rose K, Salur S, Schnetzer S, Seitz C, Somalwar S, Stone R, Thomas S, Walker M, Cerizza G, Hollingsworth M, Spanier S, Yang ZC, York A, Bouhali O, Eusebi R, Flanagan W, Gilmore J, Kamon T, Khotilovich V, Montalvo R, Osipenkov I, Pakhotin Y, Perloff A, Roe J, Safonov A, Sakuma T, Suarez I, Tatarinov A, Toback D, Akchurin N, Damgov J, Dragoiu C, Dudero PR, Jeong C, Kovitanggoon K, Lee SW, Libeiro T, Volobouev I, Appelt E, Delannoy AG, Greene S, Gurrola A, Johns W, Maguire C, Mao Y, Melo A, Sharma M, Sheldon P, Snook B, Tuo S, Velkovska J, Arenton MW, Boutle S, Cox B, Francis B, Goodell J, Hirosky R, Ledovskoy A, Lin C, Neu C, Wood J, Gollapinni S, Harr R, Karchin PE, Kottachchi Kankanamge Don C, Lamichhane P, Sakharov A, Anderson M, Belknap DA, Borrello L, Carlsmith D, Cepeda M, Dasu S, Friis E, Grogg KS, Grothe M, Hall-Wilton R, Herndon M, Hervé A, Kaadze K, Klabbers P, Klukas J, Lanaro A, Lazaridis C, Loveless R, Mohapatra A, Mozer MU, Ojalvo I, Pierro GA, Ross I, Savin A, Smith WH, Swanson J. Measurement of the top-quark mass in all-jets [Formula: see text] events in pp collisions at [Formula: see text] TeV

The mass of the top quark is measured using a sample of [Formula: see text] candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at [Formula: see text] TeV in 2011 and corresponds to an integrated luminosity of 3.54 [Formula: see text]. The mass is reconstructed for each event employing a kinematic fit of the jets to a [Formula: see text] hypothesis. The top-quark mass is measured to be [Formula: see text] GeV. A combination with previously published measurements in other decay modes by CMS yields a mass of [Formula: see text] GeV.

First look: a cluster-randomized trial of ultrasound to improve pregnancy outcomes in low income country settings

BACKGROUND

In high-resource settings, obstetric ultrasound is a standard component of prenatal care used to identify pregnancy complications and to establish an accurate gestational age in order to improve obstetric care. Whether or not ultrasound use will improve care and ultimately pregnancy outcomes in low-resource settings is unknown.

METHODS/DESIGN

This multi-country cluster randomized trial will assess the impact of antenatal ultrasound screening performed by health care staff on a composite outcome consisting of maternal mortality and maternal near-miss, stillbirth and neonatal mortality in low-resource community settings. The trial will utilize an existing research infrastructure, the Global Network for Women's and Children's Health Research with sites in Pakistan, Kenya, Zambia, Democratic Republic of Congo and Guatemala. A maternal and newborn health registry in defined geographic areas which documents all pregnancies and their outcomes to 6 weeks post-delivery will provide population-based rates of maternal mortality and morbidity, stillbirth, neonatal mortality and morbidity, and health care utilization for study clusters. A total of 58 study clusters each with a health center and about 500 births per year will be randomized (29 intervention and 29 control). The intervention includes training of health workers (e.g., nurses, midwives, clinical officers) to perform ultrasound examinations during antenatal care, generally at 18-22 and at 32-36 weeks for each subject. Women who are identified as having a complication of pregnancy will be referred to a hospital for appropriate care. Finally, the intervention includes community sensitization activities to inform women and their families of the availability of ultrasound at the antenatal care clinic and training in emergency obstetric and neonatal care at referral facilities.

DISCUSSION

In summary, our trial will evaluate whether introduction of ultrasound during antenatal care improves pregnancy outcomes in rural, low-resource settings. The intervention includes training for ultrasound-naïve providers in basic obstetric ultrasonography and then enabling these trainees to use ultrasound to screen for pregnancy complications in primary antenatal care clinics and to refer appropriately.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT # 01990625).

Residential distance at birth from overhead high-voltage powerlines: childhood cancer risk in Britain 1962-2008

Background:

We extend our previous study of childhood leukaemia and proximity to high-voltage powerlines by including more recent data and cases and controls from Scotland, by considering 132-kV powerlines as well as 275 and 400 kV and by looking at greater distances from the powerlines.

Methods:

Case–control study using 53 515 children from the National Registry of Childhood Tumours 1962–2008, matched controls, and calculated distances of mother's address at child's birth to powerlines at 132, 275, and 400 kV in England, Wales and Scotland.

Results:

Our previous finding of an excess risk for leukaemia at distances out to 600 m declines over time. Relative risk and 95% confidence interval for leukaemia, 0–199 m compared with>1000 m, all voltages: 1960s 4.50 (0.97–20.83), 2000s 0.71 (0.49–1.03), aggregate over whole period 1.12 (0.90–1.38). Increased risk, albeit less strong, may also be present for 132-kV lines. Increased risk does not extend beyond 600 m for lines of any voltage.

Conclusions:

A risk declining over time is unlikely to arise from any physical effect of the powerlines and is more likely to be the result of changing population characteristics among those living near powerlines.

Jet and underlying event properties as a function of charged-particle multiplicity in proton-proton collisions at [Formula: see text]

Characteristics of multi-particle production in proton-proton collisions at [Formula: see text] are studied as a function of the charged-particle multiplicity, Nch. The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |η|<2.4 and transverse momentum pT>0.25 GeV/c. Jets are reconstructed from charged-particles only and required to have pT>5 GeV/c. The distributions of jet pT, average pT of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of Nch and compared to the predictions of the pythia and herwig event generators. Predictions without multi-parton interactions fail completely to describe the Nch-dependence observed in the data. For increasing Nch, pythia systematically predicts higher jet rates and harder pT spectra than seen in the data, whereas herwig shows the opposite trends. At the highest multiplicity, the data-model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients.

Search for top squarks in R-parity-violating supersymmetry using three or more leptons and b-tagged jets

A search for anomalous production of events with three or more isolated leptons and bottom-quark jets produced in pp collisions at √s=8 TeV is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 19.5 fb(-1) collected by the CMS experiment at the LHC in 2012. No excess above the standard model expectations is observed. The results are interpreted in the context of supersymmetric models with signatures that have low missing transverse energy arising from light top-squark pair production with R-parity-violating decays of the lightest supersymmetric particle. In two models with different R-parity-violating couplings, top squarks are excluded below masses of 1020 GeV and 820 GeV when the lightest supersymmetric particle has a mass of 200 GeV.

Searches for new physics using the tt¯ invariant mass distribution in pp collisions at √s=8 TeV

Searches for anomalous top quark-antiquark production are presented, based on pp collisions at √s=8 TeV. The data, corresponding to an integrated luminosity of 19.7 fb(-1), were collected with the CMS detector at the LHC. The observed tt¯ invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements.

Search for supersymmetry in hadronic final states with missing transverse energy using the variables αT and b-quark multiplicity in pp collisions at [Formula: see text]

An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb-1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, αT, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks.

Response inhibition and ADHD traits: correlates and heritability in a community sample

Endophenotypes or intermediate phenotypes are of great interest in neuropsychiatric genetics because of their potential for facilitating gene discovery. We evaluated response inhibition, latency and variability measures derived from the stop task as endophenotypes of ADHD by testing whether they were related to ADHD traits in the general population, heritable and shared genetic risk with ADHD traits. Participants were 16,099 children and adolescents, ages 6 to 18 years who visited a local science center. We measured ADHD traits using the Strengths and Weaknesses of ADHD-symptoms and Normal-Behavior (SWAN) rating scale and performance on the stop signal task (SST)-response inhibition (SSRT), response latency (GoRT), and response variability (GoRTSD). Regression analysis was used to assess the relationship of cognitive measures and ADHD traits while controlling for family, age, sex, ethnicity, socioeconomic status and treatment status. Heritability of ADHD and cognitive traits was estimated using SOLAR in 7,483 siblings from 3,507 families that included multiple siblings. Bivariate relationships between pairs of variables were examined. Individuals with greater ADHD trait scores had worse response inhibition, slower response latency, and greater variability. Younger participants and girls had inferior performance although the gender effects were minimal and evident in youngest participants. Inhibition, latency, variability, total ADHD traits, inattention and hyperactivity-impulsivity scores were significantly heritable. ADHD traits and inhibition, but not latency or variability were coheritable. In the largest study in the general population, we found support for the validity of response inhibition as an endophenotype of ADHD.

Measurement of the Bs(0)→μ+ μ- branching fraction and search for B(0)→μ+ μ- with the CMS experiment

Results are presented from a search for the rare decays Bs(0)→μ+ μ- and B(0)→μ+ μ- in pp collisions at sqrt[s]=7 and 8 TeV, with data samples corresponding to integrated luminosities of 5 and 20  fb(-1), respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction B(Bs(0)→μ+ μ-)=(3.0(-0.9)(+1.0))×10(-9), where the uncertainty includes both statistical and systematic contributions. An excess of Bs(0)→μ+ μ- events with respect to background is observed with a significance of 4.3 standard deviations. For the decay B(0)→μ+ μ- an upper limit of B(B(0)→μ+ μ-)<1.1×10(-9) at the 95% confidence level is determined. Both results are in agreement with the expectations from the standard model.

Inclusive search for supersymmetry using razor variables in pp collisions at √s=7 TeV

An inclusive search is presented for new heavy particle pairs produced in √s=7 TeV proton-proton collisions at the LHC using 4.7±0.1 fb(-1) of integrated luminosity. The selected events are analyzed in the 2D razor space of M(R), an event-by-event indicator of the heavy particle mass scale, and R, a dimensionless variable related to the missing transverse energy. The third-generation sector is probed using the event heavy-flavor content. The search is sensitive to generic supersymmetry models with minimal assumptions about the superpartner decay chains. No excess is observed in the number of events beyond that predicted by the standard model. Exclusion limits are derived in the CMSSM framework as well as for simplified models. Within the CMSSM parameter space considered, gluino masses up to 800 GeV and squark masses up to 1.35 TeV are excluded at 95% confidence level depending on the model parameters. The direct production of pairs of top or bottom squarks is excluded for masses as high as 400 GeV.

Search for physics beyond the standard model in events with τ leptons, jets, and large transverse momentum imbalance in pp collisions at [Formula: see text]

A search for physics beyond the standard model is performed with events having one or more hadronically decaying τ leptons, highly energetic jets, and large transverse momentum imbalance. The data sample corresponds to an integrated luminosity of 4.98 fb-1 of proton-proton collisions at [Formula: see text] collected with the CMS detector at the LHC in 2011. The number of observed events is consistent with predictions for standard model processes. Lower limits on the mass of the gluino in supersymmetric models are determined.

Measurement of masses in the [Formula: see text] system by kinematic endpoints in pp collisions at [Formula: see text]

A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for [Formula: see text] events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 fb-1 collected by the CMS experiment in pp collisions at [Formula: see text]. The analysis is based on endpoint determinations in kinematic distributions. When the neutrino and W-boson masses are constrained to their world-average values, a top-quark mass value of [Formula: see text] is obtained. When such constraints are not used, the three particle masses are obtained in a simultaneous fit. In this unconstrained mode the study serves as a test of mass determination methods that may be used in beyond standard model physics scenarios where several masses in a decay chain may be unknown and undetected particles lead to underconstrained kinematics.

Search for a standard-model-like Higgs boson with a mass in the range 145 to 1000 GeV at the LHC

A search for a standard-model-like Higgs boson in the H→WW and H→ZZ decay channels is reported, for Higgs boson masses in the range 145 Collapse

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Search for supersymmetry in pp collisions at [Formula: see text] TeV in events with a single lepton, jets, and missing transverse momentum

Results are reported from a search for new physics processes in events containing a single isolated high-transverse-momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The analysis is based on a 4.98 fb-1 sample of proton-proton collisions at a center-of-mass energy of 7 TeV, obtained with the CMS detector at the LHC. Three separate background estimation methods, each relying primarily on control samples in the data, are applied to a range of signal regions, providing complementary approaches for estimating the background yields. The observed yields are consistent with the predicted standard model backgrounds. The results are interpreted in terms of limits on the parameter space for the constrained minimal supersymmetric extension of the standard model, as well as on cross sections for simplified models, which provide a generic description of the production and decay of new particles in specific, topology based final states.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1140/epjc/s10052-013-2404-z) contains supplementary material, which is available to authorized users.

Measurement of associated production of vector bosons and top quark-antiquark pairs in pp collisions at sqrt[s]=7 TeV

The first measurement of vector-boson production associated with a top quark-antiquark pair in proton-proton collisions at sqrt[s] = 7  TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5.0  fb(-1), recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of ttZ events and a same-sign dilepton analysis of ttV (V = W or Z) events. In the trilepton channel a direct measurement of the ttZ cross section σ(ttZ) = 0.28(-0.11)(+0.14) (stat)(-0.03)(+0.06) (syst)  pb is obtained. In the dilepton channel a measurement of the ttV cross section yields σ(ttV) = 0.43(-0.15)(+0.17) (stat)(-0.07)(+0.09) (syst)  pb. These measurements have a significance, respectively, of 3.3 and 3.0 standard deviations from the background hypotheses and are compatible, within uncertainties, with the corresponding next-to-leading order predictions of 0.137(-0.016)(+0.012) and 0.306(-0.053)(+0.031)  pb.