1,449 research outputs found

    Herschel/PACS Imaging of Protostars in the HH 1-2 Outflow Complex

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    We present 70 and 160 micron Herschel science demonstration images of a field in the Orion A molecular cloud that contains the prototypical Herbig-Haro objects HH 1 and 2, obtained with the Photodetector Array Camera and Spectrometer (PACS). These observations demonstrate Herschel's unprecedented ability to study the rich population of protostars in the Orion molecular clouds at the wavelengths where they emit most of their luminosity. The four protostars previously identified by Spitzer 3.6-40 micron imaging and spectroscopy are detected in the 70 micron band, and three are clearly detected at 160 microns. We measure photometry of the protostars in the PACS bands and assemble their spectral energy distributions (SEDs) from 1 to 870 microns with these data, Spitzer spectra and photometry, 2MASS data, and APEX sub-mm data. The SEDs are fit to models generated with radiative transfer codes. From these fits we can constrain the fundamental properties of the protostars. We find luminosities in the range 12-84 L_sun and envelope densities spanning over two orders of magnitude. This implies that the four protostars have a wide range of envelope infall rates and evolutionary states: two have dense, infalling envelopes, while the other two have only residual envelopes. We also show the highly irregular and filamentary structure of the cold dust and gas surrounding the protostars as traced at 160 microns.Comment: 6 pages, 4 figures, accepted for publication in the A&A Herschel special issu

    Physical structure of the envelopes of intermediate-mass protostars

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    Context: Intermediate mass protostars provide a bridge between low- and high-mass protostars. Furthermore, they are an important component of the UV interstellar radiation field. Despite their relevance, little is known about their formation process. Aims: We present a systematic study of the physical structure of five intermediate mass, candidate Class 0 protostars. Our two goals are to shed light on the first phase of intermediate mass star formation and to compare these protostars with low- and high-mass sources. Methods: We derived the dust and gas temperature and density profiles of the sample. We analysed all existing continuum data on each source and modelled the resulting SED with the 1D radiative transfer code DUSTY. The gas temperature was then predicted by means of a modified version of the code CHT96. Results: We found that the density profiles of five out of six studied intermediate mass envelopes are consistent with the predictions of the "inside-out" collapse theory.We compared several physical parameters, like the power law index of the density profile, the size, the mass, the average density, the density at 1000 AU and the density at 10 K of the envelopes of low-, intermediate, and high-mass protostars. When considering these various physical parameters, the transition between the three groups appears smooth, suggesting that the formation processes and triggers do not substantially differ

    Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA)

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    Background: In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers. Methods: We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach. Results: We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93–1.04, P=0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89–1.06, P=0.5) mutation carriers. Conclusion: This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out. A Osorio1, R L Milne2, G Pita3, P Peterlongo4,5, T Heikkinen6, J Simard7, G Chenevix-Trench8, A B Spurdle8, J Beesley8, X Chen8, S Healey8, KConFab9, S L Neuhausen10, Y C Ding10, F J Couch11,12, X Wang11, N Lindor13, S Manoukian4, M Barile14, A Viel15, L Tizzoni5,16, C I Szabo17, L Foretova18, M Zikan19, K Claes20, M H Greene21, P Mai21, G Rennert22, F Lejbkowicz22, O Barnett-Griness22, I L Andrulis23,24, H Ozcelik24, N Weerasooriya23, OCGN23, A-M Gerdes25, M Thomassen25, D G Cruger26, M A Caligo27, E Friedman28,29, B Kaufman28,29, Y Laitman28, S Cohen28, T Kontorovich28, R Gershoni-Baruch30, E Dagan31,32, H Jernström33, M S Askmalm34, B Arver35, B Malmer36, SWE-BRCA37, S M Domchek38, K L Nathanson38, J Brunet39, T Ramón y Cajal40, D Yannoukakos41, U Hamann42, HEBON37, F B L Hogervorst43, S Verhoef43, EB Gómez García44,45, J T Wijnen46,47, A van den Ouweland48, EMBRACE37, D F Easton49, S Peock49, M Cook49, C T Oliver49, D Frost49, C Luccarini50, D G Evans51, F Lalloo51, R Eeles52, G Pichert53, J Cook54, S Hodgson55, P J Morrison56, F Douglas57, A K Godwin58, GEMO59,60,61, O M Sinilnikova59,60, L Barjhoux59,60, D Stoppa-Lyonnet61, V Moncoutier61, S Giraud59, C Cassini62,63, L Olivier-Faivre62,63, F Révillion64, J-P Peyrat64, D Muller65, J-P Fricker65, H T Lynch66, E M John67, S Buys68, M Daly69, J L Hopper70, M B Terry71, A Miron72, Y Yassin72, D Goldgar73, Breast Cancer Family Registry37, C F Singer74, D Gschwantler-Kaulich74, G Pfeiler74, A-C Spiess74, Thomas v O Hansen75, O T Johannsson76, T Kirchhoff77, K Offit77, K Kosarin77, M Piedmonte78, G C Rodriguez79, K Wakeley80, J F Boggess81, J Basil82, P E Schwartz83, S V Blank84, A E Toland85, M Montagna86, C Casella87, E N Imyanitov88, A Allavena89, R K Schmutzler90, B Versmold90, C Engel91, A Meindl92, N Ditsch93, N Arnold94, D Niederacher95, H Deißler96, B Fiebig97, R Varon-Mateeva98, D Schaefer99, U G Froster100, T Caldes101, M de la Hoya101, L McGuffog49, A C Antoniou49, H Nevanlinna6, P Radice4,5 and J Benítez1,3 on behalf of CIMB

    Differential branching fraction and angular analysis of Λb0Λμ+μ\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^- decays

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    The differential branching fraction of the rare decay Λb0Λμ+μ\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^- is measured as a function of q2q^{2}, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 \mbox{ fb}^{-1}, collected by the LHCb experiment. Evidence of signal is observed in the q2q^2 region below the square of the J/ψJ/\psi mass. Integrating over 15 < q^{2} < 20 \mbox{ GeV}^2/c^4 the branching fraction is measured as d\mathcal{B}(\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^-)/dq^2 = (1.18 ^{+ 0.09} _{-0.08} \pm 0.03 \pm 0.27) \times 10^{-7} ( \mbox{GeV}^{2}/c^{4})^{-1}, where the uncertainties are statistical, systematic and due to the normalisation mode, Λb0J/ψΛ\Lambda^{0}_{b} \rightarrow J/\psi \Lambda, respectively. In the q2q^2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (AFBlA^{l}_{\rm FB}) and hadron (AFBhA^{h}_{\rm FB}) systems are measured for the first time. In the range 15 < q^2 < 20 \mbox{ GeV}^2/c^4 they are found to be A^{l}_{\rm FB} = -0.05 \pm 0.09 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)} and A^{h}_{\rm FB} = -0.29 \pm 0.07 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)}.Comment: 27 pages, 10 figures, Erratum adde

    Study of BDKπ+πB^{-}\to DK^-\pi^+\pi^- and BDππ+πB^-\to D\pi^-\pi^+\pi^- decays and determination of the CKM angle γ\gamma

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    We report a study of the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- decays, where the neutral DD meson is detected through its decays to the Kπ±K^{\mp}\pi^{\pm} and CP-even K+KK^+K^- and π+π\pi^+\pi^- final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0~fb1^{-1}. We observe the first significant signals in the CP-even final states of the DD meson for both the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- modes, as well as in the doubly Cabibbo-suppressed DK+πD\to K^+\pi^- final state of the BDππ+πB^-\to D\pi^-\pi^+\pi^- decay. Evidence for the ADS suppressed decay BDKπ+πB^{-}\to DK^-\pi^+\pi^-, with DK+πD\to K^+\pi^-, is also presented. From the observed yields in the BDKπ+πB^-\to DK^-\pi^+\pi^-, BDππ+πB^-\to D\pi^-\pi^+\pi^- and their charge conjugate decay modes, we measure the value of the weak phase to be γ=(7419+20)o\gamma=(74^{+20}_{-19})^{\rm o}. This is one of the most precise single-measurement determinations of γ\gamma to date.Comment: 22 pages, 9 figures; All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm

    Search for the rare decays B0J/ψγB^{0}\to J/\psi \gamma and Bs0J/ψγB^{0}_{s} \to J/\psi \gamma

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    A search for the rare decay of a B0B^{0} or Bs0B^{0}_{s} meson into the final state J/ψγJ/\psi\gamma is performed, using data collected by the LHCb experiment in pppp collisions at s=7\sqrt{s}=7 and 88 TeV, corresponding to an integrated luminosity of 3 fb1^{-1}. The observed number of signal candidates is consistent with a background-only hypothesis. Branching fraction values larger than 1.7×1061.7\times 10^{-6} for the B0J/ψγB^{0}\to J/\psi\gamma decay mode are excluded at 90% confidence level. For the Bs0J/ψγB^{0}_{s}\to J/\psi\gamma decay mode, branching fraction values larger than 7.4×1067.4\times 10^{-6} are excluded at 90% confidence level, this is the first branching fraction limit for this decay.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-044.htm

    Measurement of the mass and lifetime of the Ωb\Omega_b^- baryon

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    A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb1^{-1} collected by LHCb at s=7\sqrt{s}=7 and 8 TeV, is used to reconstruct 63±963\pm9 ΩbΩc0π\Omega_b^-\to\Omega_c^0\pi^-, Ωc0pKKπ+\Omega_c^0\to pK^-K^-\pi^+ decays. Using the ΞbΞc0π\Xi_b^-\to\Xi_c^0\pi^-, Ξc0pKKπ+\Xi_c^0\to pK^-K^-\pi^+ decay mode for calibration, the lifetime ratio and absolute lifetime of the Ωb\Omega_b^- baryon are measured to be \begin{align*} \frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\ \tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the uncertainties are statistical, systematic and from the calibration mode (for τΩb\tau_{\Omega_b^-} only). A measurement is also made of the mass difference, mΩbmΞbm_{\Omega_b^-}-m_{\Xi_b^-}, and the corresponding Ωb\Omega_b^- mass, which yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2. \end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm

    Evidence for the strangeness-changing weak decay ΞbΛb0π\Xi_b^-\to\Lambda_b^0\pi^-

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    Using a pppp collision data sample corresponding to an integrated luminosity of 3.0~fb1^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay ΞbΛb0π\Xi_b^-\to\Lambda_b^0\pi^-. No bb hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be fΞbfΛb0B(ΞbΛb0π)=(5.7±1.80.9+0.8)×104{{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}, where fΞbf_{\Xi_b^-} and fΛb0f_{\Lambda_b^0} are the bΞbb\to\Xi_b^- and bΛb0b\to\Lambda_b^0 fragmentation fractions, and B(ΞbΛb0π){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) is the branching fraction. Assuming fΞb/fΛb0f_{\Xi_b^-}/f_{\Lambda_b^0} is bounded between 0.1 and 0.3, the branching fraction B(ΞbΛb0π){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) would lie in the range from (0.57±0.21)%(0.57\pm0.21)\% to (0.19±0.07)%(0.19\pm0.07)\%.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm

    A model-independent confirmation of the Z(4430)Z(4430)^- state

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    The decay B0ψ(2S)K+πB^0\to \psi(2S) K^+\pi^- is analyzed using 3 fb1\rm 3~fb^{-1} of pppp collision data collected with the LHCb detector. A model-independent description of the ψ(2S)π\psi(2S) \pi mass spectrum is obtained, using as input the KπK\pi mass spectrum and angular distribution derived directly from data, without requiring a theoretical description of resonance shapes or their interference. The hypothesis that the ψ(2S)π\psi(2S)\pi mass spectrum can be described in terms of KπK\pi reflections alone is rejected with more than 8σ\sigma significance. This provides confirmation, in a model-independent way, of the need for an additional resonant component in the mass region of the Z(4430)Z(4430)^- exotic state.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-038.htm

    A study of CPCP violation in BDhB^\mp \rightarrow Dh^\mp (h=K,πh=K,\pi) with the modes DKπ±π0D \rightarrow K^\mp \pi^\pm \pi^0, Dπ+ππ0D \rightarrow \pi^+\pi^-\pi^0 and DK+Kπ0D \rightarrow K^+K^-\pi^0

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    An analysis of the decays of BDKB^\mp \rightarrow D K^\mp and BDπB^\mp \rightarrow D \pi^\mp is presented in which the DD meson is reconstructed in the three-body final states Kπ±π0K^\mp \pi^\pm \pi^0, π+ππ0\pi^+ \pi^- \pi^0 and K+Kπ0K^+ K^- \pi^0. Using data from LHCb corresponding to an integrated luminosity of 3.0 fb1^{-1} of pppp collisions, measurements of several CPCP observables are performed. First observations are obtained of the suppressed ADS decay B[πK±π0]DπB^\mp \rightarrow [\pi^\mp K^\pm \pi^0]_D \pi^\mp and the quasi-GLW decay B[K+Kπ0]DπB^\mp \rightarrow [K^+ K^- \pi^0]_D \pi^\mp. The results are interpreted in the context of the unitarity triangle angle γ\gamma and related parameters
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