Download or read book Simultaneous Measurement of the B0 Meson Lifetime and Mixing Frequency with B0 D 1 Nu Decays written by and published by . This book was released on 2002 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the B° lifetime [tau]{sub b°} and the B°-{bar B}° oscillation frequency [Delta]m{sub d} with a sample of approximately 14,000 exclusively reconstructed B{sup 0} 2!D*− l [nu]{sub {ell}} signal events, selected from 23 million B{bar B} pairs recorded at the [Upsilon](4S) resonance with the BABAR detector at the Stanford Linear Accelerator Center. The decay position of the other B is determined with the remaining tracks in the event, and its b-quark flavor at the time of decay is determined with a tagging algorithm that exploits the correlation between the flavor of the b-quark and the charges of its decay products. The lifetime and oscillation frequency are measured simultaneously with an unbinned maximum-likelihood ([Delta]t) that uses, for each event, the measured difference in decay times of the two B mesons ([Delta]t), the calculated uncertainty on [Delta]t, the signal and background probabilities, and b-quark tagging information for the other B. The results are [tau]{sub B{sup 0}} = (1.523{sub -0.023}{sup +0.024} ± 0.022) ps and [Delta]m{sub d} = (0.492 ± 0.018 ± 0.013) ps−1.

Download or read book Simultaneous Measurement of the B0 Meson Lifetime and Mixing Frequency with B0 D 1 Nu Decays written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the B[sup 0] lifetime[tau][sub b[sup 0]] and the B[sup 0]-[bar B][sup 0] oscillation frequency[Delta]m[sub d] with a sample of approximately 14,000 exclusively reconstructed B[sup 0][yields] D*[sup -][ell][sup+][nu][sub[ell]] signal events, selected from 23 million B[bar B] pairs recorded at the[Upsilon](4S) resonance with the BABAR detector at the Stanford Linear Accelerator Center. The decay position of the other B is determined with the remaining tracks in the event, and its b-quark flavor at the time of decay is determined with a tagging algorithm that exploits the correlation between the flavor of the b-quark and the charges of its decay products. The lifetime and oscillation frequency are measured simultaneously with an unbinned maximum-likelihood ([Delta]t) that uses, for each event, the measured difference in decay times of the two B mesons ([Delta]t), the calculated uncertainty on[Delta]t, the signal and background probabilities, and b-quark tagging information for the other B. The results are[tau][sub B[sup 0]]= (1.523[sub -0.023][sup+0.024][+-] 0.022) ps and[Delta]m[sub d]= (0.492[+-] 0.018[+-] 0.013) ps[sup -1].

Download or read book A MEASUREMENT OF THE LIFETIME AND MIXING FREQUENCY OF NEUTRAL B MESONS WITH SEMILEPTONIC DECAYS IN THE BABAR DETECTOR written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutral B meson, consisting of a b quark and an anti-d quark, can mix (oscillate) to its own anti-particle through second-order weak interactions. The measurement of the mixing frequency can constrain the quark mixing matrix in the Standard Model of particle physics. The PEP-II B-factory at the Stanford Linear Accelerator Center provides a very large data sample that enables us to make measurements with much higher precisions than previous measurements, and to probe physics beyond the Standard Model. The lifetime of the neutral B meson[tau][sub B0] and the B[sup 0]-[bar B][sup 0] mixing frequency[Delta]m[sub d] are measured with a sample of approximately 14,000 exclusively reconstructed B[sup 0][yields] D*[sup -][ell][sup+][nu][sub[ell]] signal events, selected from 23 million B[bar B] pairs recorded at the[Upsilon](4S)resonance with the BABAR detector at the asymmetric-energy e[sup+]e[sup -] collider, PEP-II. The decay position of the exclusively reconstructed B is determined by the charged tracks in the final state, and its b-quark flavor at the time of decay is known unambiguously from the charge of the lepton. The decay position of the other B is determined inclusively, and its b-quark flavor at the time of decay is determined (tagged) with the charge of tracks in the final state, where identified leptons or kaons give the most information. The decay time difference of two B mesons in the event is calculated from the distance between their decay vertices and the Lorentz boost of the center of mass. Additional samples of approximately 50,000 events are selected for studies of background events. The lifetime and mixing frequency, along with wrong-tag probabilities and the time-difference resolution function, are measured simultaneously with an unbinned maximum-likelihood fit that uses, for each event, the measured difference in B decay times ([Delta]t), the calculated uncertainty on[Delta]t, the signal and background probabilities, and b-quark tagging for the other B meson. The results are[tau][sub B[sup 0]]= (1.523[sub -0.023][sup+0.024][+-] 0.022) ps and[Delta]m[sub d]= (0.492[+-] 0.018[+-] 0.013) ps[sup -1], where the first error is statistical and the second is systematic. The statistical correlation coefficient between[tau][sub B[sup 0]] and[Delta]m[sub d] is -0.22. This result is consistent with the current world average values, the total errors are comparable with other most-precise measurements.

Download or read book Measurement of the bar B Lifetime and of the B bar B Oscillation Frequency Using Partially Reconstructed bar B D L anti nu sub L Decays written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a simultaneous measurement of the {bar B}° lifetime [tau](B°) and mixing parameter [Delta]m{sub d}. They use a sample of about 50000 {bar B}° --> D* 1 {anti {nu}}(l) partially reconstructed decays identified with the BABAR detector at the PEP-II storage ring at SLAC, where the flavor of the other B meson is determined from the charge of another high momentum lepton in the same event. The preliminary results are: tau(B°) = (1.50 ± 0.008(stat.) ± 0.030(syst.)) ps, [Delta]m{sub d} = (0.523 ± 0.004(stat.) ± 0.007(syst.)) p{sup s}( -1).

Download or read book A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics describes the fundamental building blocks of the Universe and their basic interactions. The model naturally describes the time evolution of the basic particles, of which lifetime and mixing are two examples. The neutral B meson, consisting of a bottom quark and an oppositely charged down quark, enjoys a lifetime of about 1.5 ps and the special property of mixing with its antiparticle partner, the [bar B][sup 0]. That is, due to second order weak interactions, the B[sup 0] meson can change into a [bar B][sup 0] meson and back again as it evolves through time. The details of this behavior offer an opportunity to closely examine the Standard Model. In this dissertation, I report on a measurement of the lifetime and mixing frequency of the neutral B meson. Using the semileptonic decay channel B[sup 0] [yields] D*[sup -][ell][sup +][bar [nu]][sub [ell]], we select more than 68,000 signal and background candidates from about 23 million B[bar B] pairs collected in 1999-2000 with the BABAR detector located at the Stanford Linear Accelerator Center. The other B in the event is reconstructed inclusively. By constructing a master probability density function that describes the distribution of decay time differences in the sample, we use a maximum likelihood technique to simultaneously extract the B[sup 0] lifetime and mixing parameters with precision comparable to the year 2000 world average. The results are [tau][sub B[sup 0]] = (1.523[sub -0.023][sup +0.024] [+-] 0.022) ps and [Delta]m[sub d] = (0.492 [+-] 0.018 [+-] 0.013) ps[sup -1]. The statistical correlation coefficient between [tau][sub B[sup 0]] and [Delta]m[sub d] is -0.22. I describe in detail several cutting-edge strategies this analysis uses to study these phenomena, laying important groundwork for the future. I also discuss several extensions of this work to include possible measurements of higher order parameters such as [Delta][Lambda][sub d].

Download or read book A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays written by T. Meyer and published by . This book was released on 2003 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics describes the fundamental building blocks of the Universe and their basic interactions. The model naturally describes the time evolution of the basic particles, of which lifetime and mixing are two examples. The neutral B meson, consisting of a bottom quark and an oppositely charged down quark, enjoys a lifetime of about 1.5 ps and the special property of mixing with its antiparticle partner, the {bar B}{sup 0}. That is, due to second order weak interactions, the B{sup 0} meson can change into a {bar B}{sup 0} meson and back again as it evolves through time. The details of this behavior offer an opportunity to closely examine the Standard Model. In this dissertation, I report on a measurement of the lifetime and mixing frequency of the neutral B meson. Using the semileptonic decay channel B{sup 0} {yields} D*{sup -}{ell}{sup +}{bar {nu}}{sub {ell}}, we select more than 68,000 signal and background candidates from about 23 million B{bar B} pairs collected in 1999-2000 with the BABAR detector located at the Stanford Linear Accelerator Center. The other B in the event is reconstructed inclusively. By constructing a master probability density function that describes the distribution of decay time differences in the sample, we use a maximum likelihood technique to simultaneously extract the B{sup 0} lifetime and mixing parameters with precision comparable to the year 2000 world average. The results are {tau}{sub B{sup 0}} = (1.523{sub -0.023}{sup +0.024} {+-} 0.022) ps and {Delta}m{sub d} = (0.492 {+-} 0.018 {+-} 0.013) ps{sup -1}. The statistical correlation coefficient between {tau}{sub B{sup 0}} and {Delta}m{sub d} is -0.22. I describe in detail several cutting-edge strategies this analysis uses to study these phenomena, laying important groundwork for the future. I also discuss several extensions of this work to include possible measurements of higher order parameters such as {Delta}{Lambda}{sub d}.

Download or read book ODRZYWOL PRZYTYK written by and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Measurement of the Neutral B Meson Lifetime Using Partially Reconstructed B0 D pi Decays written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutral B meson lifetime has been measured with the data collected by the BABAR detector at the PEP-II storage ring during the year 2000 for a total integrated luminosity of 20.3 fb[sup -1]. The B[sup 0][yields] D*[sup -][pi][sup+] decays have been selected with a partial reconstruction method in which only the fast pion from the B[sup 0] decay and the slow pion from D*[sup -][yields][bar D][sup 0][pi][sup -] are reconstructed. The B[sup 0] lifetime has been measured to be 1.510[+-] 0.040[+-] 0.038 ps with a sample of 6971[+-] 241 reconstructed signal events.

Download or read book Measurement of the B0 Meson Lifetime with Partial Reconstruction of B0 D pi and B0 D rho Decays written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutral B meson lifetime is measured with the data collected by the BABAR detector at the PEP-II storage ring during the years 1999 and 2000, with a total integrated luminosity of 20.7 fb[sup -1]. The decays B[sup 0][yields] D*[sup -][pi][sup+] and B[sup 0][yields] D*[sup -][rho][sup+] are selected with a partial-reconstruction technique, yielding samples of 6970[+-] 240 and 5520[+-] 250 signal events, respectively. With these events, the B[sup 0] lifetime is measured to be 1.533[+-] 0.034 (stat.)[+-] 0.038 (syst.) ps. This measurement serves as a test and validation of procedures required to measure the CP violation parameter sin (2[beta]+[gamma]) with partial reconstruction of these modes.

Download or read book Measurement of B0 and B Lifetimes Using Semileptonic Decays at CDF written by and published by . This book was released on 2010 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lifetime measurements for B0 and B+ are presented using semileptonic decays of B mesons from 360 pb-1 of data collected by CDF's lepton plus displaced track trigger. The decays B 2!l[nu]DX, where D is either D +, D0, or D* +, are partially reconstructed from a muon or electron, a displaced track, and a fully reconstructed charm meson. The B 0 and B+ lifetimes are obtained from an unbinned maximum-likelihood fit to the proper decay length distributions. The measured lifetimes are [tau]B 0 = 1.527 ± 0.012(stat.) ± 0.023(syst.)ps and [tau]B + = 1.629 ± 0.013(stat.) ± 0.025(syst.)ps.

Download or read book Measurement of the B c Meson Lifetime Using B c2 J Psi L X Decays written by and published by . This book was released on 2008 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a measurement of the average proper decay time of the B±c mesons, the ground state of bottom and charm quark bound states. The lifetime measurement is carried out in the decay modes B±c → J/[Psi] + e± + X and B±c → J/[Psi] + [mu]± + X, where the J/[Psi] decays as J/[Psi] → [mu]+[mu]- and the X are unmeasured particles such as ve or v[mu]. The data are collect by the CDF II detector which measures the properties of particles created in √s = 1.96 TeV p$\bar{p}$ collisions delivered by the Fermilab Tevatron. This measurement uses ~ 1 fb-1 of integrated luminosity. The measured average proper decay time of B±c mesons, [tau] = 0.475-0.049+0.053(stat.) ± 0.018(syst.) ps, is competitive with the most precise measurements in the world and confirms previous measurements and theoretical predictions.

Download or read book Measurement of the Lifetime of the B sup O sub S Meson from D sub S l sup Plus Correlations written by and published by . This book was released on 1996 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lifetime of the B{sub s}° meson is measured using the semileptonic decay B{sub s}° → D{sub s}−l{sup {plus}}[nu]X. The data sample consists of approximately 110 pb−1 of p{ovr p} collisions at √s = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider. There are 254±21 D{sub s}−l{sup {plus}} signal events where the D{sub s}{sup {plus}} is reconstructed through its decay mode D{sub s}− → [phi][pi]−, [phi] → K{sup {plus}}K−. Using these events, the B{sub s}° meson lifetime is determined to be [tau](B{sub s}°) = 1.37{sup {plus}0.14}{sub -0.12}(stat.)±0.04(syst.) ps. The B{sub s}° meson proper decay length distribution has been examined for a lifetime difference between the two CP eigenstates of the B{sub s}° meson, B{sub s}{sup H} and B{sub s}{sup L}. 12 refs., 3 figs., 1 tab.

Download or read book Search for New Physics Using Radiative B Meson Decays and Lifetime Measurment of the B Meson with the Belle II Experiment written by Reem Rasheed and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: After the Big Bang matter and antimatter were present in equal amounts. Today, however, everything we see, is made almost entirely of matter. A fundamental ingredient to explain this asymmetry between matter and antimatter is the violation of the CP (Charge Parity) symmetry. CP violation has been observed but quantitatively not enough to explain the huge asymmetry. The Belle II experiment in Japan studies the particles produced in electron-positron collisions at the SuperKEKB collider, the highest intensity collider in the World, allowing a high precision measurements of the known sources of CP violation and looking for new ones. In my PhD, I worked on measuring the CP violation in B meson radiative decays (decays with photon in final state) particularly promising thanks to their high sensitivity to possible new processes. Following this analysis, I started a new measurement of the B mesons lifetime where I could verify the robustness of the tools used in the CP violation measurement.

Download or read book Measurement of the B c Meson Lifetime Using B c u2192 J L X Decays written by and published by . This book was released on 2008 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a measurement of the average proper decay time of the B±c mesons, the ground state of bottom and charm quark bound states. The lifetime measurement is carried out in the decay modes B±c → J/? + e± + X and B±c → J/? + ?± + X, where the J/? decays as J/? → ?+?- and the X are unmeasured particles such as ve or v?. The data are collect by the CDF II detector which measures the properties of particles created in √s = 1.96 TeV p$ar{p}$ collisions delivered by the Fermilab Tevatron. This measurement uses ̃1 fb-1 of integrated luminosity. The measured average proper decay time of B±c mesons, ? = 0.475-0.049+0.053(stat.) ± 0.018(syst.) ps, is competitive with the most precise measurements in the world and confirms previous measurements and theoretical predictions.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of the B sub S Meson Lifetime at CDF written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton-antiproton collision data corresponding to a total integrated luminosity of [approximately] 21 pb[sup [minus]1] were collected with the CDF detector at the Fermilab Tevatron collider during 1992--1993. The lifetime of the B[sub s] meson is measured using events from the semileptonic decay B[sub s] [yields] [ell][sup +][nu]D[sub s][sup [minus]]X and from the exclusive decay B[sub s] [yields] J/[psi][phi]. For the semileptonic decay channel, 76 [ell][sup +]D[sub s][sup [minus]] signal events are selected where the D[sub s] is identified via the decay D[sub s][sup [minus]] [yields] [phi][pi][sup [minus]], [phi] [yields] K[sup +]K[sup [minus]]. From this sample the B[sub s] meson lifetime is determined to be [tau][sub s] = 1.42[sub [minus]0.23][sup +0.27] (stat.)[sub [minus]0.11][sup +0.11] (syst.) ps. In the J/[psi][phi] channel, 11 events are used and the lifetime is found to be [tau][sub s] = 1.74[sub [minus]0.60][sup +0.90] (stat.)[sub [minus]0.07][sup +0.07] (syst.) ps.

Download or read book Measurement of the Lifetime of the B sup O sub S Meson from D sup Minus sub S ell sup Plus Correlations written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The lifetime of the B[sub s][sup 0] meson is measured using the semileptonic decay B[sub s][sup 0][r-arrow] D[sub s][sup[minus]]l[sup[plus]][nu]X. The data sample consists of approximately 110 pb[sup[minus]1] of p[ovr p] collisions at[radical]s= 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider. There are 254[plus-minus]21 D[sub s][sup[minus]]l[sup[plus]] signal events where the D[sub s][sup[plus]] is reconstructed through its decay mode D[sub s][sup[minus]][r-arrow][phi][pi][sup[minus]], [phi][r-arrow] K[sup[plus]]K[sup[minus]]. Using these events, the B[sub s][sup 0] meson lifetime is determined to be[tau](B[sub s][sup 0])[equals] 1.37[sup[plus]0.14][sub[minus]0.12](stat.)[plus-minus]0.04(syst.) ps. The B[sub s][sup 0] meson proper decay length distribution has been examined for a lifetime difference between the two CP eigenstates of the B[sub s][sup 0] meson, B[sub s][sup H] and B[sub s][sup L]. 12 refs., 3 figs., 1 tab.