Size-resolved cloud condensation nuclei concentration measurements in the Arctic: two case studies from the summer of 2008

Zá,bori, J.,Rastak, N.,Yoon, Y. J.,Riipinen, I.,Strö,m, J. Copernicus GmbH 2015 Atmospheric Chemistry and Physics Vol.15 No.23

<P>Abstract. The Arctic is one of the most vulnerable regions affected by climate change. Extensive measurement data are needed to understand the atmospheric processes governing this vulnerability. Among these, data describing cloud formation potential are of particular interest, since the indirect effect of aerosols on the climate system is still poorly understood. In this paper we present, for the first time, size-resolved cloud condensation nuclei (CCN) data obtained in the Arctic. The measurements were conducted during two periods in the summer of 2008: one in June and one in August, at the Zeppelin research station (78°54´ N, 11°53´ E) in Svalbard. Trajectory analysis indicates that during the measurement period in June 2008, air masses predominantly originated from the Arctic, whereas the measurements from August 2008 were influenced by mid-latitude air masses. CCN supersaturation (SS) spectra obtained on the 27 June, before size-resolved measurements were begun, and spectra from the 21 and 24 August, conducted before and after the measurement period, revealed similarities between the 2 months. From the ratio between CCN concentration and the total particle number concentration (CN) as a function of dry particle diameter (Dp) at a SS of 0.4 %, the activation diameter (D50), corresponding to CCN / CN = 0.50, was estimated. D50 was found to be 60 and 67 nm for the examined periods in June and August 2008, respectively. Corresponding D50 hygroscopicity parameter (κ) values were estimated to be 0.4 and 0.3 for June and August 2008, respectively. These values can be compared to hygroscopicity values estimated from bulk chemical composition, where κ was calculated to be 0.5 for both June and August 2008. While the agreement between the 2 months is reasonable, the difference in κ between the different methods indicates a size dependence in the particle composition, which is likely explained by a higher fraction of inorganics in the bulk aerosol samples. </P>

Production of [FORMULA OMISSION] and [FORMULA OMISSION] in p–Pb collisions at [FORMULA OMISSION] TeV

Adamov&aacute,, D.,Aggarwal, M. M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, S.,Ahn, S. U.,Aiola, S.,Akindinov, A.,Alam, S. N.,Albuquerque, D. S. D.,Aleksandrov, D.,Alessandro, B. Springer 2017 European Physical Journal C Vol.77 No.6

<P>The transverse momentum distributions of the strange and double-strange hyperon resonances ([FORMULA OMISSION], [FORMULA OMISSION]) produced in p–Pb collisions at [FORMULA OMISSION] TeV were measured in the rapidity range [FORMULA OMISSION] for event classes corresponding to different charged-particle multiplicity densities, [FORMULA OMISSION]d[FORMULA OMISSION]/d[FORMULA OMISSION]. The mean transverse momentum values are presented as a function of [FORMULA OMISSION]d[FORMULA OMISSION]/d[FORMULA OMISSION], as well as a function of the particle masses and compared with previous results on hyperon production. The integrated yield ratios of excited to ground-state hyperons are constant as a function of [FORMULA OMISSION]d[FORMULA OMISSION]/d[FORMULA OMISSION]. The equivalent ratios to pions exhibit an increase with [FORMULA OMISSION]d[FORMULA OMISSION]/d[FORMULA OMISSION], depending on their strangeness content.</P>

J/<i>ψ</i> production as a function of charged-particle pseudorapidity density in p–Pb collisions at _{s NN} = 5.02 TeV

Adamov&aacute,, D.,Aggarwal, M.M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahn, S.U.,Aiola, S.,Akindinov, A.,Alam, S.N.,Albuquerque, D.S.D.,Aleksandrov, D.,Alessandro, B.,Alex North-Holland Pub. Co 2018 Physics letters. Section B Vol.776 No.-

<P><B>Abstract</B></P> <P>We report measurements of the inclusive J/<I>ψ</I> yield and average transverse momentum as a function of charged-particle pseudorapidity density d <SUB> N ch </SUB> / d η in p–Pb collisions at <SUB> s NN </SUB> = 5.02 TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/<I>ψ</I> yield with normalised d <SUB> N ch </SUB> / d η , measured at mid-rapidity, is observed at mid-rapidity and backward rapidity. At forward rapidity, a saturation of the relative yield is observed for high charged-particle multiplicities. The normalised average transverse momentum at forward and backward rapidities increases with multiplicity at low multiplicities and saturates beyond moderate multiplicities. In addition, the forward-to-backward nuclear modification factor ratio is also reported, showing an increasing suppression of J/<I>ψ</I> production at forward rapidity with respect to backward rapidity for increasing charged-particle multiplicity.</P>

Measurement of Z⁰-boson production at large rapidities in Pb–Pb collisions at _{s NN} = 5.02 TeV

Acharya, S.,Adamov&aacute,, D.,Adolfsson, J.,Aggarwal, M.M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahn, S.U.,Aiola, S.,Akindinov, A.,Al-Turany, M.,Alam, S.N.,Albuquerque, D.S.D.,Aleks North-Holland Pub. Co 2018 Physics letters. Section B Vol.780 No.-

<P><B>Abstract</B></P> <P>The production of <SUP> Z 0 </SUP> bosons at large rapidities in Pb–Pb collisions at <SUB> s NN </SUB> = 5.02 TeV is reported. <SUP> Z 0 </SUP> candidates are reconstructed in the dimuon decay channel ( <SUP> Z 0 </SUP> → <SUP> μ + </SUP> <SUP> μ − </SUP> ), based on muons selected with pseudo-rapidity − 4.0 < η < − 2.5 and <SUB> p T </SUB> > 20 GeV/ c . The invariant yield and the nuclear modification factor, <SUB> R AA </SUB> , are presented as a function of rapidity and collision centrality. The value of <SUB> R AA </SUB> for the 0–20% central Pb–Pb collisions is 0.67 ± 0.11 (stat.) ± 0.03 (syst.) ± 0.06 (corr. syst.) , exhibiting a deviation of 2.6<I>σ</I> from unity. The results are well-described by calculations that include nuclear modifications of the parton distribution functions, while the predictions using vacuum PDFs deviate from data by 2.3<I>σ</I> in the 0–90% centrality class and by 3<I>σ</I> in the 0–20% central collisions.</P>

A combinatorial constraint satisfaction problem dichotomy classification conjecture

Neš,etř,il, Jaroslav,Siggers, Mark H.,Zá,dori, L&aacute,szló Elsevier 2010 European journal of combinatorics : Journal europ& Vol.31 No.1

<P><B>Abstract</B></P><P>We further generalise a construction–the <I>fibre construction</I>–that was developed in an earlier paper of the first two authors. The extension in this paper gives a polynomial-time reduction of CSP(H) for any relational system H to CSP(P) for any relational system P that meets a certain technical partition condition, that of being <SUB>K3</SUB>-<I>partitionable</I>.</P><P>Moreover, we define an equivalent condition on P, that of being <I>block projective</I>, and using this show that our construction proves NP-completeness for exactly those CSPs that are conjectured to be NP-complete by the CSP dichotomy classification conjecture made by Bulatov, Jeavons and Krohkin, and by Larose and Zádori. We thus provide two new combinatorial versions of the CSP dichotomy classification conjecture.</P><P>As with our previous version of the fibre construction, we are able to address restricted versions of the dichotomy conjecture. In particular, we reduce the Feder–Hell–Huang conjecture to the CSP dichotomy classification conjecture, and we prove the Kostochka–Nešetřil–Smolíková conjecture. Although these results were proved independently by Jonsson et al. and Kun respectively, we give different, shorter, proofs.</P>

Isomer spectroscopy of neutron-rich ¹⁶⁸Tb₁₀₃

Gurgi, L.A.,Regan, P.H.,Sö,derströ,m, P.-A.,Watanabe, H.,Walker, P.M.,Podoly&aacute,k, Zs.,Nishimura, S.,Berry, T.A.,Doornenbal, P.,Lorusso, G.,Isobe, T.,Baba, H.,Xu, Z.Y.,Sakurai, H.,Sumikama Elsevier 2017 Radiation physics and chemistry Vol.140 No.-

<P>In-flight fission of a 345 MeV per nucleon U-238 primary beam on a 2 mm thick Be-9 target has been used to produce and study the decays of a range of neutron-rich nuclei centred around the doubly mid-shell nucleus Dy-170 at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified event by-event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive silicon active stopper which allowed pixelated correlations between implants and their subsequent beta-decay. Discrete gamma-ray transitions emitted following decays from either metastable states or excited states populated following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr3) fast-timing scintillation detectors from the FATIMA collaboration. This paper presents the internal decay of a metastable isomeric excited state in the odd-odd nucleus Tb-168, which corresponds to a single proton-neutron hole configuration in the valence maximum nucleus Dy-170. These data represent the first information on excited states in this nucleus, which is the most neutron-rich odd-odd isotope of terbium (Z=65) studied to date. Nilsson configurations associated with an axially symmetric, prolate-deformed nucleus are proposed for the Tb-168 ground state the observed isomeric state by comparison with Blocked BCS-Nilsson calculations.</P>

THE TAOS PROJECT: RESULTS FROM SEVEN YEARS OF SURVEY DATA

Zhang, Z.-W.,Lehner, M. J.,Wang, J.-H.,Wen, C.-Y.,Wang, S.-Y.,King, S.-K.,Granados, &Aacute,. P.,Alcock, C.,Axelrod, T.,Bianco, F. B.,Byun, Y.-I.,Chen, W. P.,Coehlo, N. K.,Cook, K. H.,de Pater, I.,Kim American Institute of Physics 2013 The Astronomical journal Vol.146 No.1

<P>The Taiwanese-American Occultation Survey (TAOS) aims to detect serendipitous occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (<10<SUP>–3</SUP> events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS monitors typically ~500 stars simultaneously at a 5 Hz readout cadence with four telescopes located at Lulin Observatory in central Taiwan. In this paper, we report the results of the search for small Kuiper Belt objects (KBOs) in seven years of data. No occultation events were found, resulting in a 95% c.l. upper limit on the slope of the faint end of the KBO size distribution of q = 3.34-3.82, depending on the surface density at the break in the size distribution at a diameter of about 90 km.</P>

The 8th International Comparison of Absolute Gravimeters 2009: the first Key Comparison (CCM.G-K1) in the field of absolute gravimetry

Jiang, Z,P&aacute,link&aacute,š,, V,Arias, F E,Liard, J,Merlet, S,Wilmes, H,Vitushkin, L,Robertsson, L,Tisserand, L,Pereira Dos Santos, F,Bodart, Q,Falk, R,Baumann, H,Mizushima, S,Mä,kinen, J Springer-Verlag 2012 METROLOGIA -BERLIN- Vol.49 No.6

<P>The 8th International Comparison of Absolute Gravimeters (ICAG2009) took place at the headquarters of the International Bureau of Weights and Measures (BIPM) from September to October 2009. It was the first ICAG organized as a key comparison in the framework of the CIPM Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA) (CIPM 1999). ICAG2009 was composed of a Key Comparison (KC) as defined by the CIPM MRA, organized by the Consultative Committee for Mass and Related Quantities (CCM) and designated as CCM.G-K1. Participating gravimeters and their operators came from national metrology institutes (NMIs) or their designated institutes (DIs) as defined by the CIPM MRA. A Pilot Study (PS) was run in parallel in order to include gravimeters and their operators from other institutes which, while not signatories of the CIPM MRA, nevertheless play important roles in international gravimetry measurements. The aim of the CIPM MRA is to have international acceptance of the measurement capabilities of the participating institutes in various fields of metrology. The results of CCM.G-K1 thus constitute an accurate and consistent gravity reference traceable to the SI (International System of Units), which can be used as the global basis for geodetic, geophysical and metrological observations of gravity. The measurements performed afterwards by the KC participants can be referred to the international metrological reference, i.e. they are SI-traceable.</P><P>The ICAG2009 was complemented by a number of associated measurements: the Relative Gravity Campaign (RGC2009), high-precision levelling and an accurate gravity survey in support of the BIPM watt balance project. The major measurements took place at the BIPM between July and October 2009. Altogether 24 institutes with 22 absolute gravimeters (one of the 22 AGs was ultimately withdrawn) and nine relative gravimeters participated in the ICAG/RGC campaign.</P><P>This paper is focused on the absolute gravity campaign. We review the history of the ICAGs and present the organization, data processing and the final results of the ICAG2009.</P><P>After almost thirty years of hosting eight successive ICAGs, the CIPM decided to transfer the responsibility for piloting the future ICAGs to NMIs, although maintaining a supervisory role through its Consultative Committee for Mass and Related Quantities.</P>

H Λ 3 and H ‾ Λ ‾ 3 lifetime measurement in Pb–Pb collisions at _{s NN} = 5.02 TeV via two-body decay

Acharya, S.,Adamov&aacute,, D.,Adhya, S.P.,Adler, A.,Adolfsson, J.,Aggarwal, M.M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, S.,Ahn, S.U.,Akindinov, A.,Al-Turany, M.,Alam, S.N.,Alb Elsevier 2019 Physics letters: B Vol.797 No.-

<P><B>Abstract</B></P> <P>An improved value for the lifetime of the (anti-)hypertriton has been obtained using the data sample of Pb–Pb collisions at <SUB> s NN </SUB> = 5.02 TeV collected by the ALICE experiment at the LHC. The (anti-)hypertriton has been reconstructed via its charged two-body mesonic decay channel and the lifetime has been determined from an exponential fit to the d<I>N</I>/d(<I>ct</I>) spectrum. The measured value, τ = 242 − 38 + 34 (stat.) ± 17 (syst.) ps, is compatible with representative theoretical predictions, thus contributing to the solution of the longstanding hypertriton lifetime puzzle.</P>

Flow Dominance and Factorization of Transverse Momentum Correlations in Pb-Pb Collisions at the LHC

Adam, J.,Adamov&aacute,, D.,Aggarwal, M. M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, S.,Ahn, S. U.,Aiola, S.,Akindinov, A.,Alam, S. N.,Albuquerque, D. S. D.,Aleksandrov, D.,Aless American Physical Society 2017 Physical review letters Vol.118 No.16

<P>We present the first measurement of the two-particle transverse momentum differential correlation function, P-2 = <Delta pT Delta p(T)>/ < p(T)>(2), in Pb-Pb collisions at root s(NN) = 2.76 TeV. Results for P-2 are reported as a function of the relative pseudorapidity (Delta eta) and azimuthal angle (Delta phi) between two particles for different collision centralities. The Delta phi dependence is found to be largely independent of Delta eta for broken vertical bar Delta eta broken vertical bar >= 0.9. In the 5% most central Pb-Pb collisions, the two-particle transverse momentum correlation function exhibits a clear double-hump structure around Delta phi=pi (i. e., on the away side), which is not observed in number correlations in the same centrality range, and thus provides an indication of the dominance of triangular flow in this collision centrality. Fourier decompositions of P-2, studied as a function of the collision centrality, show that correlations at broken vertical bar Delta eta broken vertical bar >= 0.9 can be well reproduced by a flow ansatz based on the notion that measured transverse momentum correlations are strictly determined by the collective motion of the system.</P>