The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
A Anastassov - One of the best experts on this subject based on the ideXlab platform.
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precision top quark Mass Measurement at cdf
Physical Review Letters, 2012Co-Authors: T Aaltonen, Dante Amidei, Silvia Amerio, A Anastassov, A Annovi, J Antos, Lvarez B GonzalezAbstract:We present a precision Measurement of the top-quark Mass using the full sample of Tevatron √s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb(-1). Using a sample of tt¯ candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark Masses and the invariant Mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark Mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise Measurement of the top-quark Mass, M(top)=172.85±0.71(stat)±0.85(syst) GeV/c(2).
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top quark Mass Measurement using the template method at cdf
Physical Review D, 2011Co-Authors: T Aaltonen, Dante Amidei, Silvia Amerio, A Anastassov, Alvarez B Gonzalez, A Annovi, J Antos, G ApollinariAbstract:We present a Measurement of the top quark Mass in the lepton+jets and dilepton channels of t$$\bar{t}$$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of p$$\bar{p}$$ collisions at Tevatron with √s = 1.96 TeV, collected with the CDF II detector. The Measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark Masses from different jets-to-quarks combinations and the invariant Mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark Mass and mT2, a variable related to the transverse Mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark Mass of Mtop = 172.1±1.1 (stat)±0.9 (syst) GeV/c2.
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top quark Mass Measurement in the lepton plus jets channel using a modified matrix element method
Physical Review D, 2009Co-Authors: T Aaltonen, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, A Anastassov, Alvarez B Gonzalez, A Annovi, J AntosAbstract:We report a Measurement of the top quark Mass, m{sub t}, obtained from pp collisions at {radical}(s)=1.96 TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9 fb{sup -1}. We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of m{sub t} and a parameter JES (jet energy scale) that determines in situ the calibration of the jet energies. We use a neural network discriminant to distinguish signal from background events. We also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, we find m{sub t}=172.7{+-}1.8(stat+JES){+-}1.2(syst) GeV/c{sup 2}.
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observation and Mass Measurement of the baryon ξb
Physical Review Letters, 2007Co-Authors: Terhi Aaltonen, A Abulencia, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, A Anastassov, THILO AFFOLDER, M Albrow, K AnikeevAbstract:We report the observation and Measurement of the Mass of the bottom, strange baryon Ξb- through the decay chain Ξb-→J/ψΞ-, where J/ψ→μ+μ-, Ξ-→Λπ-, and Λ→pπ-. A signal is observed whose probability of arising from a background fluctuation is 6.6×10-15, or 7.7 Gaussian standard deviations. The Ξb- Mass is measured to be 5792.9±2.5(stat) ±1.7(syst)MeV/c2. © 2007 The American Physical Society.
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top quark Mass Measurement from dilepton events at cdf ii with the matrix element method
Physical Review D, 2006Co-Authors: A Abulencia, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, THILO AFFOLDER, M Albrow, D Acosta, D Ambrose, A AnastassovAbstract:We describe a Measurement of the top quark Mass using events with two charged leptons collected by the CDF II detector from p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron. The likelihood in top Mass is calculated for each event by convoluting the leading order matrix element describing q{bar q} {yields} t{bar t} {yields} b{ell}{nu}{sub {ell}}{bar b}{ell}{prime} {nu}{sub {ell}}, with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of 340 pb{sup -1}, we observe 33 candidate events and measure M{sub top} = 165.2 {+-} 6.1(stat.) {+-} 3.4(syst.) GeV/c{sup 2}. This Measurement represents the first application of this method to events with two charged leptons and is the most precise single Measurement of the top quark Mass in this channel.
J Antos - One of the best experts on this subject based on the ideXlab platform.
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precision top quark Mass Measurement at cdf
Physical Review Letters, 2012Co-Authors: T Aaltonen, Dante Amidei, Silvia Amerio, A Anastassov, A Annovi, J Antos, Lvarez B GonzalezAbstract:We present a precision Measurement of the top-quark Mass using the full sample of Tevatron √s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb(-1). Using a sample of tt¯ candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark Masses and the invariant Mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark Mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise Measurement of the top-quark Mass, M(top)=172.85±0.71(stat)±0.85(syst) GeV/c(2).
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top quark Mass Measurement using the template method at cdf
Physical Review D, 2011Co-Authors: T Aaltonen, Dante Amidei, Silvia Amerio, A Anastassov, Alvarez B Gonzalez, A Annovi, J Antos, G ApollinariAbstract:We present a Measurement of the top quark Mass in the lepton+jets and dilepton channels of t$$\bar{t}$$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of p$$\bar{p}$$ collisions at Tevatron with √s = 1.96 TeV, collected with the CDF II detector. The Measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark Masses from different jets-to-quarks combinations and the invariant Mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark Mass and mT2, a variable related to the transverse Mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark Mass of Mtop = 172.1±1.1 (stat)±0.9 (syst) GeV/c2.
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top quark Mass Measurement in the lepton plus jets channel using a modified matrix element method
Physical Review D, 2009Co-Authors: T Aaltonen, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, A Anastassov, Alvarez B Gonzalez, A Annovi, J AntosAbstract:We report a Measurement of the top quark Mass, m{sub t}, obtained from pp collisions at {radical}(s)=1.96 TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9 fb{sup -1}. We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of m{sub t} and a parameter JES (jet energy scale) that determines in situ the calibration of the jet energies. We use a neural network discriminant to distinguish signal from background events. We also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, we find m{sub t}=172.7{+-}1.8(stat+JES){+-}1.2(syst) GeV/c{sup 2}.
David C Muddiman - One of the best experts on this subject based on the ideXlab platform.
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parts per billion Mass Measurement accuracy achieved through the combination of multiple linear regression and automatic gain control in a fourier transform ion cyclotron resonance Mass spectrometer
Analytical Chemistry, 2007Co-Authors: Keith D Williams, David C MuddimanAbstract:Fourier transform ion cyclotron resonance Mass spectrometry has the ability to achieve unprecedented Mass Measurement accuracy (MMA); MMA is one of the most significant attributes of Mass spectrometric Measurements as it affords extraordinary molecular specificity. However, due to space-charge effects, the achievable MMA significantly depends on the total number of ions trapped in the ion cyclotron resonance (ICR) cell for a particular Measurement. Even through the use of automatic gain control (AGC), the total ion population is not constant between spectra. Multiple linear regression calibration in conjunction with AGC is utilized in these experiments to formally account for the differences in total ion population in the ICR cell between the external calibration spectra and experimental spectra. This ability allows for the extension of dynamic range of the instrument and for the mean MMA values to remain less than 1 part-per-million (ppm). In addition, multiple linear regression calibration is used to account for both differences in total ion population in the ICR cell as well as relative ion abundance of a given species, which also affords mean MMA values at the parts-per-billion (ppb) level.
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parts per billion Mass Measurement accuracy achieved through the combination of multiple linear regression and automatic gain control in a fourier transform ion cyclotron resonance Mass spectrometer
Analytical Chemistry, 2007Co-Authors: Keith D Williams, David C MuddimanAbstract:Fourier transform ion cyclotron resonance Mass spectrometry has the ability to achieve unprecedented Mass Measurement accuracy (MMA); MMA is one of the most significant attributes of Mass spectrometric Measurements as it affords extraordinary molecular specificity. However, due to space-charge effects, the achievable MMA significantly depends on the total number of ions trapped in the ion cyclotron resonance (ICR) cell for a particular Measurement. Even through the use of automatic gain control (AGC), the total ion population is not constant between spectra. Multiple linear regression calibration in conjunction with AGC is utilized in these experiments to formally account for the differences in total ion population in the ICR cell between the external calibration spectra and experimental spectra. This ability allows for the extension of dynamic range of the instrument and for the mean MMA values to remain less than 1 part-per-million (ppm). In addition, multiple linear regression calibration is used to ac...
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effect of post excitation radius on ion abundance Mass Measurement accuracy and isotopic distributions in fourier transform ion cyclotron resonance Mass spectrometry
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Adam M Hawkridge, Angelito I Nepomuceno, Stephanie L Lovik, Christopher J Mason, David C MuddimanAbstract:We report an evaluation of a modern Fourier transform ion cyclotron resonance Mass spectrometry (FT-ICR-MS) instrument to determine the general trend of post-excitation radius on total ion abundance, Mass Measurement accuracy, and isotopic distributions for internally calibrated Mass spectra. The optimum post-excitation radius was determined using total ion abundance, Mass Measurement accuracy (MMA), and isotope ratios. However, despite the utility of internal calibration for achieving ultimate MMA, the internal calibrant ions were insufficient for compensating for sub-optimum ICR cell conditions. The findings presented herein underscore the importance of determining the optimal post-excitation radius in FT-ICR-MS to achieve high ion abundance (low limits of detection), high MMA, and valid isotopic distributions.
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precise Mass Measurement of a double stranded 500 base pair 309 kda polymerase chain reaction product by negative ion electrospray ionization fourier transform ion cyclotron resonance Mass spectrometry
Rapid Communications in Mass Spectrometry, 1999Co-Authors: David C Muddiman, Allison P Null, James C HannisAbstract:Electrospray ionization Fourier transform ion cyclotron resonance Mass spectrometry (ESI-FTICRMS) has been used to determine the Mass of a double-stranded 500 base-pair (bp) polymerase chain reaction (PCR) product with an average theoretical Mass of the blunt-ended (i.e. unadenylated) species of 308 859.35 Da. The PCR product was generated from the linearized bacteriophage Lambda genome which is a double-stranded template. Utilization of ethanol precipitation in tandem with a rapid microdialysis step to purify and desalt the PCR product was crucial to obtain a precise Mass Measurement. The PCR product (0.8 pmol/µL) was electrosprayed from a solution containing 75% acetonitrile, 25 mM piperidine, and 25 mM imidazole and was infused at a rate of 200 nL/min. The average molecular Mass and the corresponding precision were determined using the charge-states ranging from 172 to 235 net negative charges. The experimental Mass and corresponding precision (reported as the 95% confidence interval of the mean) was 309 406 +/- 27 Da (87 ppm). The Mass accuracy was compromised due to the fact that the PCR generates multiple products when using Taq polymerase due to the non-template directed 3'-adenylation. This results in a mixture of three PCR products with nearly identical Mass (i.e. blunt-ended, mono-adenylated and di-adenylated) with unknown relative abundances that were not resolved in the spectrum. Thus, the experimental Mass will be a weighted average of the three species which, under our experimental conditions, reflects a nearly equal concentration of the mono- and di-adenylated species. This report demonstrates that precise Mass Measurements of PCR products up to 309 kDa (500 bp) can be routinely obtained by ESI-FTICR requiring low femtomole amounts. Copyright 1999 John Wiley & Sons, Ltd.
Rick A Flurer - One of the best experts on this subject based on the ideXlab platform.
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accurate Mass Measurement using fourier transform ion cyclotron resonance Mass spectrometry for structure elucidation of designer drug analogs of tadalafil vardenafil and sildenafil in herbal and pharmaceutical matrices
Rapid Communications in Mass Spectrometry, 2006Co-Authors: Samuel R Gratz, Bryan M Gamble, Rick A FlurerAbstract:Phosphodiesterase type 5 (PDE-5) inhibitors are a class of drugs used primarily in the treatment of erectile dysfunction. The Food and Drug Administration (FDA) approved PDE-5 inhibitors include sildenafil citrate, vardenafil hydrochloride and tadalafil. In this study, accurate Mass Measurements were made by electrospray ionization (ESI) using Fourier transform ion cyclotron resonance Mass spectrometry (FTICRMS) to elucidate the structures of sildenafil, tadalafil and vardenafil analogs that were found in products marketed as dietary supplements. Initial detection of these analogs was accomplished through routine screening of suspect samples by liquid chromatography/electrospray ionization multi-stage Mass spectrometry (LC/ESI-MS(n)) on a low-resolution ion trap instrument. The chromatographic behavior and Mass spectrometric fragmentation patterns observed were often similar to those observed for FDA approved PDE-5 inhibitors. The Mass accuracy and resolving power associated with FTICRMS allows for the determination of elemental compositions. Elucidation of the product ion structures for the analogs was accomplished through the use of accurate Mass Measurements with the aid of Mass Frontier software (version 4.0). Using FTICRMS, accurate Masses with Measurement errors averaging <0.4 ppm were achieved, allowing assignment of one possible elemental formula to each fragment ion. The Mass Measurement errors associated with [M + H](+) for the analogs aminotadalafil, piperidino vardenafil, hydroxyacetildenafil and piperidino acetildenafil were 0.1, 0.0, 0.1 and 0.5 ppm, respectively. Based on the accuracy of the Measurements, structural assignments could be made with a high degree of confidence.
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accurate Mass Measurement using fourier transform ion cyclotron resonance Mass spectrometry for structure elucidation of designer drug analogs of tadalafil vardenafil and sildenafil in herbal and pharmaceutical matrices
Rapid Communications in Mass Spectrometry, 2006Co-Authors: Samuel R Gratz, Bryan M Gamble, Rick A FlurerAbstract:Phosphodiesterase type 5 (PDE-5) inhibitors are a class of drugs used primarily in the treatment of erectile dysfunction. The Food and Drug Administration (FDA) approved PDE-5 inhibitors include sildenafil citrate, vardenafil hydrochloride and tadalafil. In this study, accurate Mass Measurements were made by electrospray ionization (ESI) using Fourier transform ion cyclotron resonance Mass spectrometry (FTICRMS) to elucidate the structures of sildenafil, tadalafil and vardenafil analogs that were found in products marketed as dietary supplements. Initial detection of these analogs was accomplished through routine screening of suspect samples by liquid chromatography/electrospray ionization multi-stage Mass spectrometry (LC/ESI-MSn) on a low-resolution ion trap instrument. The chromatographic behavior and Mass spectrometric fragmentation patterns observed were often similar to those observed for FDA approved PDE-5 inhibitors. The Mass accuracy and resolving power associated with FTICRMS allows for the determination of elemental compositions. Elucidation of the product ion structures for the analogs was accomplished through the use of accurate Mass Measurements with the aid of Mass Frontier software (version 4.0). Using FTICRMS, accurate Masses with Measurement errors averaging <0.4 ppm were achieved, allowing assignment of one possible elemental formula to each fragment ion. The Mass Measurement errors associated with [M + H]+ for the analogs aminotadalafil, piperidino vardenafil, hydroxyacetildenafil and piperidino acetildenafil were 0.1, 0.0, 0.1 and 0.5 ppm, respectively. Based on the accuracy of the Measurements, structural assignments could be made with a high degree of confidence. Published in 2006 by John Wiley & Sons, Ltd.
Silvia Amerio - One of the best experts on this subject based on the ideXlab platform.
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precision top quark Mass Measurement at cdf
Physical Review Letters, 2012Co-Authors: T Aaltonen, Dante Amidei, Silvia Amerio, A Anastassov, A Annovi, J Antos, Lvarez B GonzalezAbstract:We present a precision Measurement of the top-quark Mass using the full sample of Tevatron √s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb(-1). Using a sample of tt¯ candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark Masses and the invariant Mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark Mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise Measurement of the top-quark Mass, M(top)=172.85±0.71(stat)±0.85(syst) GeV/c(2).
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top quark Mass Measurement using the template method at cdf
Physical Review D, 2011Co-Authors: T Aaltonen, Dante Amidei, Silvia Amerio, A Anastassov, Alvarez B Gonzalez, A Annovi, J Antos, G ApollinariAbstract:We present a Measurement of the top quark Mass in the lepton+jets and dilepton channels of t$$\bar{t}$$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of p$$\bar{p}$$ collisions at Tevatron with √s = 1.96 TeV, collected with the CDF II detector. The Measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark Masses from different jets-to-quarks combinations and the invariant Mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark Mass and mT2, a variable related to the transverse Mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark Mass of Mtop = 172.1±1.1 (stat)±0.9 (syst) GeV/c2.
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top quark Mass Measurement in the lepton plus jets channel using a modified matrix element method
Physical Review D, 2009Co-Authors: T Aaltonen, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, A Anastassov, Alvarez B Gonzalez, A Annovi, J AntosAbstract:We report a Measurement of the top quark Mass, m{sub t}, obtained from pp collisions at {radical}(s)=1.96 TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9 fb{sup -1}. We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of m{sub t} and a parameter JES (jet energy scale) that determines in situ the calibration of the jet energies. We use a neural network discriminant to distinguish signal from background events. We also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, we find m{sub t}=172.7{+-}1.8(stat+JES){+-}1.2(syst) GeV/c{sup 2}.
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observation and Mass Measurement of the baryon ξb
Physical Review Letters, 2007Co-Authors: Terhi Aaltonen, A Abulencia, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, A Anastassov, THILO AFFOLDER, M Albrow, K AnikeevAbstract:We report the observation and Measurement of the Mass of the bottom, strange baryon Ξb- through the decay chain Ξb-→J/ψΞ-, where J/ψ→μ+μ-, Ξ-→Λπ-, and Λ→pπ-. A signal is observed whose probability of arising from a background fluctuation is 6.6×10-15, or 7.7 Gaussian standard deviations. The Ξb- Mass is measured to be 5792.9±2.5(stat) ±1.7(syst)MeV/c2. © 2007 The American Physical Society.
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top quark Mass Measurement from dilepton events at cdf ii with the matrix element method
Physical Review D, 2006Co-Authors: A Abulencia, Dante Amidei, J Adelman, T Akimoto, Silvia Amerio, THILO AFFOLDER, M Albrow, D Acosta, D Ambrose, A AnastassovAbstract:We describe a Measurement of the top quark Mass using events with two charged leptons collected by the CDF II detector from p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron. The likelihood in top Mass is calculated for each event by convoluting the leading order matrix element describing q{bar q} {yields} t{bar t} {yields} b{ell}{nu}{sub {ell}}{bar b}{ell}{prime} {nu}{sub {ell}}, with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of 340 pb{sup -1}, we observe 33 candidate events and measure M{sub top} = 165.2 {+-} 6.1(stat.) {+-} 3.4(syst.) GeV/c{sup 2}. This Measurement represents the first application of this method to events with two charged leptons and is the most precise single Measurement of the top quark Mass in this channel.