3,780 research outputs found
Exploring Lifetime Effects in Femtoscopy
We investigate the role of lifetime effects from resonances and emission
duration tails in femtoscopy at RHIC in two Blast-Wave models. We find the
non-Gaussian components compare well with published source imaged data, but the
value of R_out obtained from Gaussian fits is not insensitive to the
non-Gaussian contributions when realistic acceptance cuts are applied to
models.Comment: 5 pages, 2 figure
Solution of the RHIC HBT puzzle with Gaussian initial conditions
It is argued that the consistent description of the transverse-momentum
spectra, elliptic flow, and the HBT radii in the relativistic heavy-ion
collisions studied at RHIC may be obtained within the hydrodynamic model if one
uses the Gaussian profile for the initial energy density in the transverse
plane. Moreover, we show that the results obtained in the scenario with an
early start of hydrodynamics (at the proper time tau0 = 0.25 fm) are
practically equivalent to the results obtained in the model where the
hydrodynamics is preceded by the free-streaming stage of partons (in the proper
time interval 0.25 fm < tau < 1 fm) which suddenly equilibrate and with the
help of the Landau matching conditions are transformed into the hydrodynamic
regime (at the proper time tau0 = 1 fm).Comment: talk presented by WF at SQM2008 Conferenc
Highly-anisotropic and strongly-dissipative hydrodynamics with transverse expansion
A recently formulated framework of highly-anisotropic and
strongly-dissipative hydrodynamics (ADHYDRO) is used to describe the evolution
of matter created in ultra-relativistic heavy-ion collisions. New developments
of the model contain: the inclusion of asymmetric transverse expansion
(combined with the longitudinal boost-invariant flow) and comparisons of the
model results with the RHIC data, which have become possible after coupling of
ADHYDRO with THERMINATOR. Various soft-hadronic observables (the
transverse-momentum spectra, the elliptic flow coefficient v_2, and the HBT
radii) are calculated for different initial conditions characterized by the
value of the initial pressure asymmetry. We find that as long as the initial
energy density profile is unchanged the calculated observables remain
practically the same. This result indicates the insensitivity of the analyzed
observables to the initial anisotropy of pressure and suggests that the
complete thermalization of the system may be delayed to easily acceptable times
of about 1 fm/c
Early dynamics of transversally thermalized matter
We argue that the idea that the parton system created in relativistic
heavy-ion collisions is formed in a state with transverse momenta close to
thermodynamic equilibrium and its subsequent dynamics at early times is
dominated by pure transverse hydrodynamics of the perfect fluid is compatible
with the data collected at RHIC. This scenario of early parton dynamics may
help to solve the problem of early equilibration.Comment: 4 pages, 2 figures, Talk given by M. Chojnacki at Quark Matter 2008,
Jaipur, Indi
Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Vinyl Cyanide in Orion-KL
New laboratory data of CHCHCN (vinyl cyanide) in its ground and
vibrationally excited states at the microwave to THz domain allow searching for
these excited state transitions in the Orion-KL line survey.
Frequency-modulated spectrometers combined into a single broadband 50-1900 GHz
spectrum provided measurements of CHCHCN covering a spectral range of
18-1893 GHz, whose assignments was confirmed by Stark modulation spectra in the
18-40 GHz region and by ab-initio anharmonic force field calculations. For
analyzing the emission lines of CHCHCN species detected in Orion-KL we used
the excitation and radiative transfer code (MADEX) at LTE conditions. The
rotational transitions of the ground state of this molecule emerge from four
cloud components of hot core nature which trace the physical and chemical
conditions of high mass star forming regions in the Orion-KL Nebula. The total
column density of CHCHCN in the ground state is (3.00.9)x10
cm. We report on the first interstellar detection of transitions in the
v10=1/(v11=1,v15=1) dyad in space, and in the v11=2 and v11=3 states in
Orion-KL. The lowest energy vibrationally excited states of vinyl cyanide such
as v11=1 (at 328.5 K), v15=1 (at 478.6 K), v11=2 (at 657.8 K), the
v10=1/(v11=1,v15=1) dyad (at 806.4/809.9 K), and v11=3 (at 987.9 K) are
populated under warm and dense conditions, so they probe the hottest parts of
the Orion-KL source. Column density and rotational and vibrational temperatures
for CHCHCN in their ground and excited states, as well as for the
isotopologues, have been constrained by means of a sample of more than 1000
lines in this survey. Moreover, we present the detection of methyl isocyanide
(CHNC) for the first time in Orion-KL and a tentative detection of vinyl
isocyanide (CHCHNC) and give column density ratios between the cyanide and
isocyanide isomers.Comment: 46 pages, 22 figures, 14 tables, 9 online table
Altering the properties of graphene on Cu(111) by intercalation of potassium bromide
The catalytic growth on transition metal surfaces provides a clean and controllable route to obtain defect-free, monocrystalline graphene. However, graphene's optical and electronic properties are diminished by the interaction with the metal substrate. One way to overcome this obstacle is the intercalation of atoms and molecules decoupling the graphene and restoring its electronic structure. We applied noncontact atomic force microscopy to study the structural and electric properties of graphene on clean Cu(111) and after the adsorption of KBr or NaCl. By means of Kelvin probe force microscopy, a change in graphene's work function has been observed after the deposition of KBr, indicating a changed graphene-substrate interaction. Further measurements of single-electron charging events as well as X-ray photoelectron spectroscopy confirmed an electronic decoupling of the graphene islands by KBr intercalation. The results have been compared with density functional theory calculations, supporting our experimental findings
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Exploring Lifetime Effects in Femtoscopy
We investigate the role of lifetime effects from resonances and emission duration tails in femtoscopy at RHIC in two Blast-Wave models. We find the non-Gaussian components compare well with published source imaged data, but the value of R{sub out} obtained from Gaussian fits is not insensitive to the non-Gaussian contributions when realistic acceptance cuts are applied to models
Solid-state reference electrodes based on carbon nanotubes and polyacrylate membranes
A novel potentiometric solid-state reference electrode containing single-walled carbon nanotubes as the transducer layer between a polyacrylate membrane and the conductor is reported here. Single-walled carbon nanotubes act as an efficient transducer of the constant potentiometric signal originating from the reference membrane containing the Ag/AgCl/Cl− ions system, and they are needed to obtain a stable reference potentiometric signal. Furthermore, we have taken advantage of the light insensitivity of single-walled carbon nanotubes to improve the analytical performance characteristics of previously reported solid-state reference electrodes. Four different polyacrylate polymers have been selected in order to identify the most efficient reservoir for the Ag/AgCl system. Finally, two different arrangements have been assessed: (1) a solid-state reference electrode using photo-polymerised n-butyl acrylate polymer and (2) a thermo-polymerised methyl methacrylate:n-butyl acrylate (1:10) polymer. The sensitivity to various salts, pH and light, as well as time of response and stability, has been tested: the best results were obtained using single-walled carbon nanotubes and photo-polymerised n-butyl acrylate polymer. Water transport plays an important role in the potentiometric performance of acrylate membranes, so a new screening test method has been developed to qualitatively assess the difference in water percolation between the polyacrylic membranes studied. The results presented here open the way for the true miniaturisation of potentiometric systems using the excellent properties of single-walled carbon nanotubes
Simultaneous measurement of the muon neutrino charged-current cross section on oxygen and carbon without pions in the final state at T2K
Authors: K. Abe,56 N. Akhlaq,45 R. Akutsu,57 A. Ali,32 C. Alt,11 C. Andreopoulos,54,34 L. Anthony,21 M. Antonova,19 S. Aoki,31
A. Ariga,2 T. Arihara,59 Y. Asada,69 Y. Ashida,32 E. T. Atkin,21 Y. Awataguchi,59 S. Ban,32 M. Barbi,46 G. J. Barker,66
G. Barr,42 D. Barrow,42 M. Batkiewicz-Kwasniak,15 A. Beloshapkin,26 F. Bench,34 V. Berardi,22 L. Berns,58 S. Bhadra,70
S. Bienstock,53 S. Bolognesi,6 T. Bonus,68 B. Bourguille,18 S. B. Boyd,66 A. Bravar,13 D. Bravo Berguño,1 C. Bronner,56
S. Bron,13 A. Bubak,51 M. Buizza Avanzini ,10 T. Campbell,7 S. Cao,16 S. L. Cartwright,50 M. G. Catanesi,22 A. Cervera,19
D. Cherdack,17 N. Chikuma,55 G. Christodoulou,12 M. Cicerchia,24,†J. Coleman,34 G. Collazuol,24 L. Cook,42,28
D. Coplowe,42 A. Cudd,7 A. Dabrowska,15 G. De Rosa,23 T. Dealtry,33 S. R. Dennis,34 C. Densham,54 F. Di Lodovico,30
N. Dokania,39 S. Dolan,12 T. A. Doyle,33 O. Drapier,10 J. Dumarchez,53 P. Dunne,21 A. Eguchi,55 L. Eklund,14
S. Emery-Schrenk,6 A. Ereditato,2 A. J. Finch,33 G. Fiorillo,23 C. Francois,2 M. Friend,16,‡ Y. Fujii,16,‡ R. Fujita,55
D. Fukuda,40 R. Fukuda,60 Y. Fukuda,37 K. Fusshoeller,11 C. Giganti,53 M. Gonin,10 A. Gorin,26 M. Guigue,53
D. R. Hadley,66 J. T. Haigh,66 P. Hamacher-Baumann,49 M. Hartz,62,28 T. Hasegawa,16,‡ S. Hassani,6 N. C. Hastings,16
Y. Hayato,56,28 A. Hiramoto,32 M. Hogan,8 J. Holeczek,51 N. T. Hong Van,20,27 T. Honjo,41 F. Iacob,24 A. K. Ichikawa,32
M. Ikeda,56 T. Ishida,16,‡ M. Ishitsuka,60 K. Iwamoto,55 A. Izmaylov,26 N. Izumi,60 M. Jakkapu,16 B. Jamieson,67
S. J. Jenkins,50 C. Jesús-Valls,18 M. Jiang,32 P. Jonsson,21 C. K. Jung,39,§ X. Junjie,57 P. B. Jurj,21 M. Kabirnezhad,42
A. C. Kaboth,48,54 T. Kajita,57,§ H. Kakuno,59 J. Kameda,56 D. Karlen,63,62 S. P. Kasetti,35 Y. Kataoka,56 Y. Katayama,69
T. Katori,30 Y. Kato,56 E. Kearns,3,28,§ M. Khabibullin,26 A. Khotjantsev,26 T. Kikawa,32 H. Kikutani,55 H. Kim,41 S. King,30
J. Kisiel,51 A. Knight,66 T. Kobata,41 T. Kobayashi,16,‡ L. Koch,42 T. Koga,55 A. Konaka,62 L. L. Kormos,33 Y. Koshio,40,§
A. Kostin,26 K. Kowalik,38 H. Kubo,32 Y. Kudenko,26,∥ N. Kukita,41 S. Kuribayashi,32 R. Kurjata,65 T. Kutter,35 M. Kuze,58
L. Labarga,1 J. Lagoda,38 M. Lamoureux,24 D. Last,43 M. Lawe,33 M. Licciardi,10 R. P. Litchfield,14 S. L. Liu,39 X. Li,39
A. Longhin,24 L. Ludovici,25 X. Lu,42 T. Lux,18 L. N. Machado,23 L. Magaletti,22 K. Mahn,36 M. Malek,50 S. Manly,47
L. Maret,13 A. D. Marino,7 L. Marti-Magro,56,28 T. Maruyama,16,‡ T. Matsubara,16 K. Matsushita,55 V. Matveev,26
C. Mauger,43 K. Mavrokoridis,34 E. Mazzucato,6 N. McCauley,34 J. McElwee,50 K. S. McFarland,47 C. McGrew,39
A. Mefodiev,26 C. Metelko,34 M. Mezzetto,24 A. Minamino,69 O. Mineev,26 S. Mine,5 M. Miura,56,§ L. Molina Bueno,11
S. Moriyama,56,§ Th. A. Mueller,10 L. Munteanu,6 S. Murphy,11 Y. Nagai,7 T. Nakadaira,16,‡ M. Nakahata,56,28
Y. Nakajima,56 A. Nakamura,40 K. Nakamura,28,16,‡ S. Nakayama,56,28 T. Nakaya,32,28 K. Nakayoshi,16,‡ C. E. R. Naseby,21
T. V. Ngoc,20,¶ K. Niewczas,68 K. Nishikawa,16,* Y. Nishimura,29 E. Noah,13 T. S. Nonnenmacher,21 F. Nova,54 P. Novella,19
J. Nowak,33 J. C. Nugent,14 H. M. O’Keeffe,33 L. O’Sullivan,50 T. Odagawa,32 T. Ogawa,16 R. Okada,40 K. Okumura,57,28
T. Okusawa,41 S. M. Oser,4,62 R. A. Owen,45 Y. Oyama,16,‡ V. Palladino,23 V. Paolone,44 M. Pari,24 W. C. Parker,48
S. Parsa,13 J. Pasternak,21 M. Pavin,62 D. Payne,34 G. C. Penn,34 L. Pickering,36 C. Pidcott,50 G. Pintaudi,69 C. Pistillo,2
B. Popov,53,** K. Porwit,51 M. Posiadala-Zezula,64 A. Pritchard,34 B. Quilain,10 T. Radermacher,49 E. Radicioni,22
B. Radics,11 P. N. Ratoff,33 C. Riccio,39 E. Rondio,38 S. Roth,49 A. Rubbia,11 A. C. Ruggeri,23 C. Ruggles,14 A. Rychter,65
K. Sakashita,16,‡ F. Sánchez,13 G. Santucci,70 C. M. Schloesser,11 K. Scholberg,9,§ M. Scott,21 Y. Seiya,41,††T. Sekiguchi,16,‡
H. Sekiya,56,28,§ D. Sgalaberna,11 A. Shaikhiev,26 A. Shaykina,26 M. Shiozawa,56,28 W. Shorrock,21 A. Shvartsman,26
M. Smy,5 J. T. Sobczyk,68 H. Sobel,5,28 F. J. P. Soler,14 Y. Sonoda,56 S. Suvorov,26,6 A. Suzuki,31 S. Y. Suzuki,16,‡
Y. Suzuki,28 A. A. Sztuc,21 M. Tada,16,‡ M. Tajima,32 A. Takeda,56 Y. Takeuchi,31,28 H. K. Tanaka,56,§ H. A. Tanaka,52,61
S. Tanaka,41 Y. Tanihara,69 N. Teshima,41 L. F. Thompson,50 W. Toki,8 C. Touramanis,34 T. Towstego,61 K. M. Tsui,34
T. Tsukamoto,16,‡ M. Tzanov,35 Y. Uchida,21 M. Vagins,28,5 S. Valder,66 Z. Vallari,39 D. Vargas,18 G. Vasseur,6
W. G. S. Vinning,66 T. Vladisavljevic,54 V. V. Volkov,26 T. Wachala,15 J. Walker,67 J. G. Walsh,33 Y. Wang,39 D. Wark,54,42
M. O. Wascko,21 A. Weber,54,42 R. Wendell,32,§ M. J. Wilking,39 C. Wilkinson,2 J. R. Wilson,30 K. Wood,39
C. Wret,47 K. Yamamoto,41,††C. Yanagisawa,39,‡‡ G. Yang,39 T. Yano,56 K. Yasutome,32 N. Yershov,26 M. Yokoyama,55,§
T. Yoshida,58 M. Yu,70 A. Zalewska,15 J. Zalipska,38 K. Zaremba,65 G. Zarnecki,38 M. Ziembicki,65
E. D. Zimmerman,7 M. Zito,53 S. Zsoldos,30 and A. Zykova26
(T2K Collaboration)This paper reports the first simultaneous measurement of the double differential muon neutrino chargedcurrent
cross section on oxygen and carbon without pions in the final state as a function of the outgoing
muon kinematics, made at the ND280 off-axis near detector of the T2K experiment. The ratio of the oxygen
and carbon cross sections is also provided to help validate various models’ ability to extrapolate between
carbon and oxygen nuclear targets, as is required in T2K oscillation analyses. The data are taken using a
neutrino beam with an energy spectrum peaked at 0.6 GeV. The extracted measurement is compared with
the prediction from different Monte Carlo neutrino-nucleus interaction event generators, showing particular
model separation for very forward-going muons. Overall, of the models tested, the result is best described
using local Fermi gas descriptions of the nuclear ground state with RPA suppression
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