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2019-03-16
06:10
Search for heavy neutral leptons at the NA62 experiment at CERN / Zamkovsky, Michal (Charles U.) /NA62
Search for heavy neutral lepton (HNL) production in charged kaon decays using the data collected by kaon experiments NA48/2 and NA62 at CERN are reported. Upper limits are established on the elements of the extended neutrino mixing matrix for heavy neutral lepton mass in the range 130–450 MeV, improving on the results from previous HNL production search..
2018 - 10 p. - Published in : Int. J. Mod. Phys. A 33 (2018) 1844026

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2019-03-16
06:10
Geometrodynamics and charge-like unification: On the vanishing of C, CP violation in QCD, in the limit $G_F \to 0$ / Minkowski, Peter (U. Bern, AEC ; CERN)
We present two original derivations of the restoration of C and CP symmetry within QCD, simplest in “standalone QCD” but extendable to include conserved QED, in the limit $G_F \to 0$, $\tau_{\tau} = \frac{G^2_Fm^5_{\tau}\lvert V_{ud} \rvert ^2}{64 \pi ^3}S (m_{\tau},M_Z)(1+\frac{3}{5} \frac{m^2_{\tau}-m^2_{\mu}}{M^2_W}) \times \cdot \cdot \cdot$,$G_F/(\hslash c)^3 = 1.1663787(6) \times 10^{-5} \textrm{GeV}^{-2}$..
2018 - 8 p. - Published in : Int. J. Mod. Phys. A 33 (2018) 1844008

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2019-03-16
06:10
Timing resolution studies of the optical part of the AFP Time-of-flight detector / Chytka, L (Palacky U.) ; Avoni, G (INFN, Bologna ; U. Bologna, DIFA) ; Brandt, A (Texas U., Arlington) ; Cavallaro, E (Barcelona, IFAE) ; Davis, P M (Alberta U.) ; Förster, F (Barcelona, IFAE) ; Hrabovsky, M (Palacky U.) ; Huang, Y (Hefei, CUST) ; Jirakova, K (Palacky U.) ; Kocian, M (SLAC) et al.
We present results of the timing performance studies of the optical part and front-end electronics of the time-of-flight subdetector prototype for the ATLAS Forward Proton (AFP) detector obtained during the test campaigns at the CERN-SPS test-beam facility (120 GeV $\pi ^+$ particles) in July 2016 and October 2016. The time-of-flight (ToF) detector in conjunction with a 3D silicon pixel tracker will tag and measure protons originating in central exclusive interactions $p + p \rightarrow p + X + p$, where the two outgoing protons are scattered in the very forward directions. [...]
2018 - 12 p. - Published in : Opt. Express 26 (2018) 8028-8039 Fulltext: PDF; External link: Fulltext

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2019-03-16
06:10
A Systematic Analysis of the Prompt Dose Distribution at the Large Hadron Collider / Stein, Oliver (CERN) ; Bilko, Kacper (CERN) ; Brugger, Markus (CERN) ; Danzeca, Salvatore (CERN) ; Di Francesca, Diego (CERN) ; Garcia Alia, Ruben (CERN) ; Kadi, Yacine (CERN) ; Li Vecchi, Gaetano (CERN) ; Martinella, Corinna (CERN)
During the operation of the Large Hadron Collider (LHC) the continuous particle losses create a mixed particle radiation field in the LHC tunnel and the adjacent caverns. Exposed electronics and accelerator components show dose dependent accelerated aging effects. [...]
2018 - 3 p. - Published in : 10.18429/JACoW-IPAC2018-WEPAF082 Fulltext: PDF;
In : 9th International Particle Accelerator Conference, Vancouver, Canada, 29 Apr - 4 May 2018, pp.WEPAF082

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2019-03-16
06:10
An Enhanced Quench Detection System for Main Quadrupole Magnets in the Large Hadron Collider / Spasic, Jelena (CERN) ; Calcoen, Daniel (CERN) ; Denz, Reiner (CERN) ; Froidbise, Vincent (CERN) ; Georgakakis, Spyridon (CERN) ; Podzorny, Tomasz (CERN) ; Siemko, Andrzej (CERN) ; Steckert, Jens (CERN)
To further improve the performance and reliability of the quench detection system (QDS) for main quadrupole magnets in the Large Hadron Collider (LHC), there is a planned upgrade of the system during the long shutdown period of the LHC in 2019-2020. While improving the already existing functionalities of quench detection for quadrupole magnets and field-bus data acquisition, the enhanced QDS will incorporate new functionalities to strengthen and improve the system operation and maintenance. [...]
2018 - 4 p. - Published in : 10.18429/JACoW-IPAC2018-WEPAF081 Fulltext: PDF;
In : 9th International Particle Accelerator Conference, Vancouver, Canada, 29 Apr - 4 May 2018, pp.WEPAF081

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2019-03-16
06:10
Observation of the 1S–2P Lyman-$\alpha$ transition in antihydrogen / Ahmadi, M (Liverpool U.) ; Alves, B X R (Aarhus U.) ; Baker, C J (Swansea U.) ; Bertsche, W (Manchester U. ; Cockcroft Inst. Accel. Sci. Tech.) ; Capra, A (TRIUMF) ; Carruth, C (UC, Berkeley) ; Cesar, C L (Rio de Janeiro Federal U.) ; Charlton, M (Swansea U.) ; Cohen, S (Ben Gurion U. of Negev) ; Collister, R (TRIUMF) et al. /ALPHA
In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. [...]
2018 - 5 p. - Published in : Nature 561 (2018) 211-215 Fulltext: PDF; External link: Interactions.org article

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2019-03-16
06:10
Anneal induced transformations of defects in hadron irradiated Si wafers and Schottky diodes / Gaubas, E (Vilnius U.) ; Ceponis, T (Vilnius U.) ; Deveikis, L (Vilnius U.) ; Meskauskaite, D (Vilnius U.) ; Pavlov, J (Vilnius U.) ; Rumbauskas, V (Vilnius U.) ; Vaitkus, J (Vilnius U.) ; Moll, M (CERN) ; Ravotti, F (CERN)
In this research, the anneal induced transformations of radiation defects have been studied in n-type and p-type CZ and FZ Si samples, irradiated with relativistic protons (24 GeV/c) and pions (300 MeV/c) using particle fluences up to $3 \times 10^{16}$ cm$^{−2}$. The temperature dependent carrier trapping lifetime (TDTL) spectroscopy method was combined with measurements of current deep level transient spectroscopy (DLTS) to trace the evolution of the prevailing radiation defects. [...]
2018 - 9 p. - Published in : Mat. Sci. Semicond. Proc. 75 (2018) 157-165

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2019-03-16
06:10
Beyond the traditional Line-of-Sight approach of cosmological angular statistics / Schöneberg, Nils (RWTH Aachen U.) ; Simonović, Marko (Princeton, Inst. Advanced Study ; CERN) ; Lesgourgues, Julien (RWTH Aachen U.) ; Zaldarriaga, Matias (Princeton, Inst. Advanced Study)
We present a new efficient method to compute the angular power spectra of large-scale structure observables that circumvents the numerical integration over Bessel functions, expanding on a recently proposed algorithm based on FFTlog. This new approach has better convergence properties. [...]
arXiv:1807.09540; TTK-18-28; TTK-18-28.- 2018-10-25 - 35 p. - Published in : JCAP 1810 (2018) 047 Fulltext: PDF; External links: 00006 Auto-correlation spectrum of number count (involving only the density source term) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,.; 00002 \textit{(Top)} Auto-correlation spectrum of number count (involving all source contributions) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,. \textit{(Bottom)} Cross-correlation between two redshift bins defined by two Gaussian windows with $(\bar{z}_1, \Delta z_1) = (1.0, 0.05)$ and $(\bar{z}_2, \Delta z_2) = (1.25, 0.05)$.; 00004 Auto-correlation spectrum of cosmic shear (or more precisely of the lensing potential $C_\ell^{\phi \phi}$) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,.; 00012 \textit{(Top)} Auto-correlation spectrum of number count (involving all source contributions) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,. \textit{(Bottom)} Cross-correlation between two redshift bins defined by two Gaussian windows with $(\bar{z}_1, \Delta z_1) = (1.0, 0.05)$ and $(\bar{z}_2, \Delta z_2) = (1.25, 0.05)$.; 00010 Number count spectra involving only density terms for a redshift bin centered at $\bar{z}=1.0$ with width $\Delta z=0.05$\,. \textit{(Top Left)} Total spectra w/o nonlinear corrections from Halofit and massive neutrinos with $M_\nu=1$~eV. \textit{(Top Right)} Impact of these two corrections on the power spectrum, computed as a relative difference (in \%) with respect to the linear spectrum of the massless neutrino model\,. \textit{(Bottom left)} Result of the new method with either the \tquote{full separability} or \tquote{semi-separability} approximations compared to the traditional line-of-sight approach. \textit{(Bottom right)} Relative difference (in \%) between the new and old methods. One can immediately see that the additional effects are well captured and the error remains at the sub-permille level.\\; 00014 \textit{(Top)} Auto-correlation spectrum of number count (involving all source contributions) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,. \textit{(Bottom)} Cross-correlation between two redshift bins defined by two Gaussian windows with $(\bar{z}_1, \Delta z_1) = (1.0, 0.05)$ and $(\bar{z}_2, \Delta z_2) = (1.25, 0.05)$.; 00005 Number count spectra involving only density terms for a redshift bin centered at $\bar{z}=1.0$ with width $\Delta z=0.05$\,. \textit{(Top Left)} Total spectra w/o nonlinear corrections from Halofit and massive neutrinos with $M_\nu=1$~eV. \textit{(Top Right)} Impact of these two corrections on the power spectrum, computed as a relative difference (in \%) with respect to the linear spectrum of the massless neutrino model\,. \textit{(Bottom left)} Result of the new method with either the \tquote{full separability} or \tquote{semi-separability} approximations compared to the traditional line-of-sight approach. \textit{(Bottom right)} Relative difference (in \%) between the new and old methods. One can immediately see that the additional effects are well captured and the error remains at the sub-permille level.\\; 00000 Auto-correlation spectrum of cosmic shear (or more precisely of the lensing potential $C_\ell^{\phi \phi}$) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,.; 00007 Auto-correlation spectrum of number count (involving only the density source term) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,.; 00008 \textit{(Top)} Auto-correlation spectrum of number count (involving all source contributions) in one redshift bin defined by a Gaussian window function with mean redshift $\bar{z}=1.0$ and width $\Delta z = 0.05$\,. \textit{(Bottom)} Cross-correlation between two redshift bins defined by two Gaussian windows with $(\bar{z}_1, \Delta z_1) = (1.0, 0.05)$ and $(\bar{z}_2, \Delta z_2) = (1.25, 0.05)$.; 00001 Number count spectra involving only density terms for a redshift bin centered at $\bar{z}=1.0$ with width $\Delta z=0.05$\,. \textit{(Top Left)} Total spectra w/o nonlinear corrections from Halofit and massive neutrinos with $M_\nu=1$~eV. \textit{(Top Right)} Impact of these two corrections on the power spectrum, computed as a relative difference (in \%) with respect to the linear spectrum of the massless neutrino model\,. \textit{(Bottom left)} Result of the new method with either the \tquote{full separability} or \tquote{semi-separability} approximations compared to the traditional line-of-sight approach. \textit{(Bottom right)} Relative difference (in \%) between the new and old methods. One can immediately see that the additional effects are well captured and the error remains at the sub-permille level.\\; 00009 Number count spectra involving only density terms for a redshift bin centered at $\bar{z}=1.0$ with width $\Delta z=0.05$\,. \textit{(Top Left)} Total spectra w/o nonlinear corrections from Halofit and massive neutrinos with $M_\nu=1$~eV. \textit{(Top Right)} Impact of these two corrections on the power spectrum, computed as a relative difference (in \%) with respect to the linear spectrum of the massless neutrino model\,. \textit{(Bottom left)} Result of the new method with either the \tquote{full separability} or \tquote{semi-separability} approximations compared to the traditional line-of-sight approach. \textit{(Bottom right)} Relative difference (in \%) between the new and old methods. One can immediately see that the additional effects are well captured and the error remains at the sub-permille level.\\; 00003 Another consequence of the Limber limit: For large $\ell$ the $t_{min}$ parameter behaves as $1/\ell$ (left), and the $|I_\ell(\nu,1)/\ell^{\nu-2}|$ is constant as in equation \ref{eq_Il_limit} (right). Note that the oscillations due to imaginary $\nu$ are correctly captured and the relative size approaches the correct constant. The black lines indicate the behavior for $\nu=-2.1+30i$ and $\epsilon=10^{-4}$, while the grey lines specify asymptotes. On the left, the grey line is $\ell^{-1}$ times an arbitrary constant (here $30/\ell$), while on the right side the constant is fixed by \ref{eq_Il_limit}. The constant for $t_{min}$ is not exactly $\log(1/\epsilon)$ because of the influence of the hypergeometric function.; 00011 An illustration of the Limber limit: For large $\ell$ the area under the curve $I_\ell(\nu,t)$ approaches $\pi^2 \ell^{\nu-3}$ when integrated from $0$ to $1$. We see that the factor $\ell^{3-\nu} \, I_\ell(\nu,t)$ approaches the constant $\pi^2$, which is an equivalent statement.; 00013 Another consequence of the Limber limit: For large $\ell$ the $t_{min}$ parameter behaves as $1/\ell$ (left), and the $|I_\ell(\nu,1)/\ell^{\nu-2}|$ is constant as in equation \ref{eq_Il_limit} (right). Note that the oscillations due to imaginary $\nu$ are correctly captured and the relative size approaches the correct constant. The black lines indicate the behavior for $\nu=-2.1+30i$ and $\epsilon=10^{-4}$, while the grey lines specify asymptotes. On the left, the grey line is $\ell^{-1}$ times an arbitrary constant (here $30/\ell$), while on the right side the constant is fixed by \ref{eq_Il_limit}. The constant for $t_{min}$ is not exactly $\log(1/\epsilon)$ because of the influence of the hypergeometric function.

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2019-03-15
11:24
Radiation damage tests of semi-conductors / Ohmori, C (KEK) ; Paoluzzi, M (CERN)
2018 - 1 p. - Published in : QST Takasaki Annual Report 2017, pp. 33 Fulltext: PDF;

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2019-03-15
07:05
LIU (LHC入射器アップグレード)-RFの現状と CERNメイラン地区加速器の広帯域化 / Ohmori, Chihiro (KEK, Tsukuba) ; Poluzzi, Mauro (CERN) ; Tamura, Fumihiko (JAEA, Ibaraki) ; Hasegawa, Katsushi (KEK, Tsukuba) ; Sugiyama, Yasuyuki (KEK, Tsukuba) ; Yoshii, Masahito (KEK, Tsukuba)
We collaborate from 2012 for the LIU-LHC Injector Upgrade Project which is required for the HiLumi LHC. This paper summarize the status of LIU-RF collaboration based on a wideband cavity loaded with a magnetic alloy material. [...]
PASJ2017-TUOL01.- 2017 - 5 p. Fulltext: PDF; External link: Fulltext

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