15 research outputs found

    Resilient Digital Image Watermarking for Document Authentication

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    Abstract—We consider the applications of the Discrete Cosine Transform (DCT) and then a Chirp coding method for producing a highly robust system for watermarking images using a block partitioning approach subject to a self-alignment strategy and bit error correction. The applications for the algorithms presented and the system developed include the copyright protection of images and Digital Right Management for image libraries, for example. However, the principal focus of the research reported in this paper is on the use of printscan and e-display-scan image authentication for use in e-tickets where QR code, for example, are embedded in a full colour image of the ticket holder. This requires that an embedding procedure is developed that is highly robust to blur, noise, geometric distortions such as rotation, shift and barrel and the partial removal of image segments, all of which are considered in regard to the resilience of the method proposed and its practical realisation in a real operating environment

    Resilient Digital Image Watermarking Using a DCT- Component Perturbation Model

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    The applications of the Discrete Cosine Transform (DCT) for Computer Generated Imagery, image processingand, in particular, image compression are well known and the DCT also forms the central kernel for a number ofdigital image watermarking methods. In this paper we consider the application of the DCT for producing a highlyrobust method of watermarking images using a block partitioning approach subject to a self-alignment strategyand bit error correction. The applications for the algorithms presented include the copyright protection of imagesand Digital Right Management for image libraries, for example. However, the principal focus of the researchreported in this paper is on the use of print-scan and e-display-scan image authentication for use in e-ticketswhere QR code, for example, are embedded in an full colour image of the ticket holder. This requires that a DCTembedding procedure is developed that is highly robust to blur, noise, geometric distortions such as rotation, shift and barrel and the partial removal of image segments, all of which are consider ed in regard to the resilience of the method proposed and its practical realisation in a real operating environment

    Study of forward Z + jet production in pp collisions at √s=7 TeV

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    A measurement of the Z(→Ό+Ό−)Z(\rightarrow\mu^+\mu^-)+jet production cross-section in pppp collisions at a centre-of-mass energy s=7\sqrt{s} = 7 TeV is presented. The analysis is based on an integrated luminosity of 1.0 fb−11.0\,\text{fb}^{-1} recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (2.0<η<4.52.0<\eta<4.5). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction.A measurement of the Z(→Ό+Ό−)Z(\rightarrow\mu^+\mu^-)+jet production cross-section in pppp collisions at a centre-of-mass energy s=7\sqrt{s} = 7 TeV is presented. The analysis is based on an integrated luminosity of 1.0 fb−11.0\,\text{fb}^{-1} recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (2.0<η<4.52.0<\eta<4.5). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction

    A study of CP violation in B-+/- -&gt; DK +/- and B-+/- -&gt; D pi(+/-) decays with D -&gt; (KSK +/-)-K-0 pi(-/+) final states

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    A first study of CP violation in the decay modes B±→[KS0K±π∓]Dh±B^\pm\to [K^0_{\rm S} K^\pm \pi^\mp]_D h^\pm and B±→[KS0K∓π±]Dh±B^\pm\to [K^0_{\rm S} K^\mp \pi^\pm]_D h^\pm, where hh labels a KK or π\pi meson and DD labels a D0D^0 or D‟0\overline{D}^0 meson, is performed. The analysis uses the LHCb data set collected in pppp collisions, corresponding to an integrated luminosity of 3 fb−1^{-1}. The analysis is sensitive to the CP-violating CKM phase Îł\gamma through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of Îł\gamma using other decay modes

    Studies of beauty baryon decays to D0ph− and Λ+ch− final states

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    Measurement of Upsilon production in collisions at root s=2.76 TeV

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    The production of ΄(1S)\Upsilon(1S), ΄(2S)\Upsilon(2S) and ΄(3S)\Upsilon(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1pb^{-1} collected in proton-proton collisions at a centre-of-mass energy of s=2.76\sqrt{s}=2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ΄\Upsilon transverse momentum and rapidity, over the ranges $p_{\rm T} Upsilon(1S) X) x B(Upsilon(1S) -> mu+mu-) = 1.111 +/- 0.043 +/- 0.044 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S) -> mu+mu-) = 0.264 +/- 0.023 +/- 0.011 nb, sigma(pp -> Upsilon(3S) X) x B(Upsilon(3S) -> mu+mu-) = 0.159 +/- 0.020 +/- 0.007 nb, where the first uncertainty is statistical and the second systematic

    Measurement of the Bc+B_c^+ meson lifetime using Bc+→J/ψΌ+ΜΌXB_c^+ \to J/\psi\mu^+ \nu_{\mu} X decays

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    The lifetime of the Bc+B_c^+ meson is measured using semileptonic decays having a J/ψJ/\psi meson and a muon in the final state. The data, corresponding to an integrated luminosity of 2 fb−12\mathrm{~fb^{-1}}, are collected by the LHCb detector in pppp collisions at a centre-of-mass energy of 8 TeV8\,\mathrm{TeV}. The measured lifetime is τ=509±8±12 fs,\tau = 509 \pm 8 \pm 12 \mathrm{~fs}, where the first uncertainty is statistical and the second is systematic.The lifetime of the Bc+B_c^+ meson is measured using semileptonic decays having a J ⁣/â€‰âŁÏˆJ\!/\!\psi meson and a muon in the final state. The data, corresponding to an integrated luminosity of 2 fb−12\mathrm{~fb^{-1}}, are collected by the LHCb detector in pppp collisions at a centre-of-mass energy of 8 TeV8\,\mathrm{TeV}. The measured lifetime is τ=509±8±12 fs,\tau = 509 \pm 8 \pm 12 \mathrm{~fs}, where the first uncertainty is statistical and the second is systematic.The lifetime of the B c + meson is measured using semileptonic decays having a J / ψ meson and a muon in the final state. The data, corresponding to an integrated luminosity of 2 fb - 1 , are collected by the LHCb detector in p p collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is τ = 509 ± 8 ± 12 fs , where the first uncertainty is statistical and the second is systematic

    Searches for Λb0\Lambda^0_{b} and Ξb0\Xi^{0}_{b} decays to KS0pπ−K^0_{\rm S} p \pi^{-} and KS0pK−K^0_{\rm S}p K^{-} final states with first observation of the Λb0→KS0pπ−\Lambda^0_{b} \rightarrow K^0_{\rm S}p \pi^{-} decay

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    A search for previously unobserved decays of beauty baryons to the final states KS0pπ−K^0_{\rm\scriptscriptstyle S} p \pi^{-} and KS0pK−K^0_{\rm\scriptscriptstyle S}p K^{-} is reported. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 1.0\,fb−1^{-1} of pppp collisions. The Λb0→K‟S0pπ−\Lambda^0_{b} \rightarrow \overline{\kern -0.2em K}^0_{\rm\scriptscriptstyle S}p \pi^{-} decay is observed with a significance of 8.6 σ8.6\,\sigma, with branching fraction \begin{eqnarray*} {\cal{B}}(\Lambda^0_{b} \rightarrow \overline{\kern -0.2em K}^0 p \pi^{-}) & = & \left( 1.26 \pm 0.19 \pm 0.09 \pm 0.34 \pm 0.05 \right) \times 10^{-5} \,, \end{eqnarray*} where the uncertainties are statistical, systematic, from the ratio of fragmentation fractions fΛ/fdf_{\Lambda}/f_{d}, and from the branching fraction of the B0→KS0π+π−B^0 \rightarrow K^0_{\rm\scriptscriptstyle S}\pi^{+}\pi^{-} normalisation channel, respectively. A first measurement is made of the CPCP asymmetry, giving \begin{eqnarray*} A_{C\!P} (\Lambda^0_{b} \rightarrow \overline{\kern -0.2em K}^0 p \pi^{-}) & = & 0.22 \pm 0.13\mathrm{\,(stat)} \pm 0.03\mathrm{\,(syst)} \, . \end{eqnarray*} No significant signals are seen for Λb0→KS0pK−\Lambda^0_{b} \rightarrow K^0_{\rm\scriptscriptstyle S}p K^{-} decays, Ξb0\Xi^{0}_{b} decays to both the KS0pπ−K^0_{\rm\scriptscriptstyle S}p \pi^{-} and KS0pK−K^0_{\rm\scriptscriptstyle S}p K^{-} final states, and the Λb0→Ds−(→KS0K−)p\Lambda^0_{b} \rightarrow D^{-}_{s} (\rightarrow K^0_{\rm\scriptscriptstyle S} K^{-}) p decay, and upper limits on their branching fractions are reported.A search for previously unobserved decays of beauty baryons to the final states KS0pπ−K^0_{\rm\scriptscriptstyle S} p \pi^{-} and KS0pK−K^0_{\rm\scriptscriptstyle S}p K^{-} is reported. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 1.0\,fb−1^{-1} of pppp collisions. The Λb0→K‟S0pπ−\Lambda^0_{b} \rightarrow \overline{\kern -0.2em K}^0_{\rm\scriptscriptstyle S}p \pi^{-} decay is observed with a significance of 8.6 σ8.6\,\sigma, with branching fraction \begin{eqnarray*} {\cal{B}}(\Lambda^0_{b} \rightarrow \overline{\kern -0.2em K}^0 p \pi^{-}) & = & \left(1.26 \pm 0.19 \pm 0.09 \pm 0.34 \pm 0.05 \right) \times 10^{-5} \,, \end{eqnarray*} where the uncertainties are statistical, systematic, from the ratio of fragmentation fractions fΛ/fdf_{\Lambda}/f_{d}, and from the branching fraction of the B0→KS0π+π−B^0 \rightarrow K^0_{\rm\scriptscriptstyle S}\pi^{+}\pi^{-} normalisation channel, respectively. A first measurement is made of the CPCP asymmetry, giving \begin{eqnarray*} A_{C/!P} (\Lambda^0_{b} \rightarrow \overline{\kern -0.2em K}^0 p \pi^{-}) & = & 0.22 \pm 0.13\mathrm{\,(stat)} \pm 0.03\mathrm{\,(syst)} \, . \end{eqnarray*} No significant signals are seen for Λb0→KS0pK−\Lambda^0_{b} \rightarrow K^0_{\rm\scriptscriptstyle S}p K^{-} decays, Ξb0\Xi^{0}_{b} decays to both the KS0pπ−K^0_{\rm\scriptscriptstyle S}p \pi^{-} and KS0pK−K^0_{\rm\scriptscriptstyle S}p K^{-} final states, and the Λb0→Ds−(→KS0K−)p\Lambda^0_{b} \rightarrow D^{-}_{s} (\rightarrow K^0_{\rm\scriptscriptstyle S} K^{-}) p decay, and upper limits on their branching fractions are reported

    Observation of associated production of a ZZ boson with a DD meson in the forward region

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    A search for associated production of a ZZ boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of 1.0fb−11.0\mathrm{fb}^{-1} of proton--proton collisions at a centre-of-mass energy of 7 TeV, collected by the LHCb experiment. Seven candidate events for associated production of a ZZ boson with a D0D^0 meson and four candidate events for a ZZ boson with a D+D^+ meson are observed with a combined significance of 5.1 standard deviations. The production cross-sections in the forward region are measured to be σZ→Ό+ÎŒâˆ’â€‰âŁ,D0=2.50±1.12±0.22pb\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} = 2.50\pm1.12\pm0.22pb σZ→Ό+ÎŒâˆ’â€‰âŁ,D+=0.44±0.23±0.03pb,\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} = 0.44\pm0.23\pm0.03pb, where the first uncertainty is statistical and the second systematic

    Updated measurements of exclusive J/ψJ/\psi and ψ(2S)\psi(2S) production cross-sections in pppp collisions at s=7\sqrt{s}=7 TeV

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    The differential cross-section as a function of rapidity has been measured for the exclusive production of J/ψJ/\psi and ψ(2S)\psi(2S) mesons in proton-proton collisions at s=7\sqrt{s}=7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pb−1^{-1}. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be σpp→J/ψ→Ό+Ό−(2.0<ηΌ±<4.5)=291±7±19 pb,σpp→ψ(2S)→Ό+Ό−(2.0<ηΌ±<4.5)=6.5±0.9±0.4 pb,\begin{array}{rl} \sigma_{pp\rightarrow J/\psi\rightarrow{\mu^+}{\mu^-}}(2.0<\eta_{\mu^\pm }<4.5)=&291\pm 7\pm19 {\rm \ pb},\\ \sigma_{pp\rightarrow\psi(2S)\rightarrow{\mu^+}{\mu^-}}(2.0<\eta_{\mu^\pm}<4.5)=&6.5\pm 0.9\pm 0.4 {\rm \ pb},\end{array} where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects.The differential cross-section as a function of rapidity has been measured for the exclusive production of J/ψJ/\psi and ψ(2S)\psi(2S) mesons in proton-proton collisions at s=7\sqrt{s}=7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pb−1^{-1}. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be σpp→J/ψ→Ό+Ό−(2.0<ηΌ±<4.5)=291±7±19 pb,σpp→ψ(2S)→Ό+Ό−(2.0<ηΌ±<4.5)=6.5±0.9±0.4 pb,\begin{array}{rl} \sigma_{pp\rightarrow J/\psi\rightarrow{\mu^+}{\mu^-}}(2.0<\eta_{\mu^\pm }<4.5)=&291\pm 7\pm19 {\rm \ pb},\\ \sigma_{pp\rightarrow\psi(2S)\rightarrow{\mu^+}{\mu^-}}(2.0<\eta_{\mu^\pm}<4.5)=&6.5\pm 0.9\pm 0.4 {\rm \ pb},\end{array} where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects.The differential cross-section as a function of rapidity has been measured for the exclusive production of J/ψJ/\psi and ψ(2S)\psi(2S) mesons in proton-proton collisions at s=7\sqrt{s}=7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pb−1^{-1}. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be σpp→J/ψ→Ό+Ό−(2.0<ηΌ±<4.5)=291±7±19 pb,σpp→ψ(2S)→Ό+Ό−(2.0<ηΌ±<4.5)=6.5±0.9±0.4 pb,\begin{array}{rl} \sigma_{pp\rightarrow J/\psi\rightarrow{\mu^+}{\mu^-}}(2.0<\eta_{\mu^\pm }<4.5)=&291\pm 7\pm19 {\rm \ pb},\\ \sigma_{pp\rightarrow\psi(2S)\rightarrow{\mu^+}{\mu^-}}(2.0<\eta_{\mu^\pm}<4.5)=&6.5\pm 0.9\pm 0.4 {\rm \ pb},\end{array} where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects
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