2,015 research outputs found

    Measurement of forward neutral pion transverse momentum spectra for s\sqrt{s} = 7TeV proton-proton collisions at LHC

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    The inclusive production rate of neutral pions in the rapidity range greater than y=8.9y=8.9 has been measured by the Large Hadron Collider forward (LHCf) experiment during LHC s=7\sqrt{s}=7\,TeV proton-proton collision operation in early 2010. This paper presents the transverse momentum spectra of the neutral pions. The spectra from two independent LHCf detectors are consistent with each other and serve as a cross check of the data. The transverse momentum spectra are also compared with the predictions of several hadronic interaction models that are often used for high energy particle physics and for modeling ultra-high-energy cosmic-ray showers.Comment: 18 Pages, 10 figures, submitted to Phys. Rev.

    The performance of the LHCf detector for hadronic showers

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    The Large Hadron Collider forward (LHCf) experiment has been designed to use the LHC to benchmark the hadronic interaction models used in cosmic-ray physics. The LHCf experiment measures neutral particles emitted in the very forward region of LHC collisions. In this paper, the performances of the LHCf detectors for hadronic showers was studied with MC simulations and beam tests. The detection efficiency for neutrons is from 60% to 70% above 500 GeV. The energy resolutions are about 40% and the position resolution is 0.1 to 1.3mm depend on the incident energy for neutrons. The energy scale determined by the MC simulations and the validity of the MC simulations were examined using 350 GeV proton beams at the CERN-SPS.Comment: 15pages, 19 figure

    Measurement of zero degree single photon energy spectra for sqrt(s) = 7TeV proton-proton collisions at LHC

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    In early 2010, the Large Hadron Collider forward (LHCf) experiment measured very forward neutral particle spectra in LHC proton-proton collisions. From a limited data set taken under the best beam conditions (low beam-gas background and low occurance of pile-up events), the single photon spectra at sqrt(s)=7TeV and pseudo-rapidity (eta) ranges from 8.81 to 8.99 and from 10.94 to infinity were obtained for the first time and are reported in this paper. The spectra from two independent LHCf detectors are consistent with one another and serve as a cross check of the data. The photon spectra are also compared with the predictions of several hadron interaction models that are used extensively for modeling ultra high energy cosmic ray showers. Despite conservative estimates for the systematic errors, none of the models agree perfectly with the measurements. A notable difference is found between the data and the DPMJET 3.04 and PYTHIA 8.145 hadron interaction models above 2TeV where the models predict higher photon yield than the data. The QGSJET II-03 model predicts overall lower photon yield than the data, especially above 2TeV in the rapidity range 8.81<eta<8.99

    Developing a High Resolution ZDC for the EIC

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    The Electron Ion Collider offers the opportunity to make un-paralleled multidimen- sional measurements of the spin structure of the proton and nuclei, as well as a study of the onset of partonic saturation at small Bjorken-x [1]. An important requirement of the physics program is the tagging of spectator neutrons and the identification of forward photons. We propose to design and build a Zero Degree Calorimeter, or ZDC, to measure photons and neutrons with excellent energy & position resolution

    First results from LHCf for forward physics in ‚ąös = 7TeV proton-proton interactions

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    The LHCf Collaboration has completed the first step of its scheduled physics program for the study of emission of neutral particles in the forward region of proton-proton (pp) interactions at LHC. Between 2009 and 2010 the LHCf experiment has successfully taken data at 900 GeV and 7TeV total energy in the center-of-mass frame of reference (CM). After a short presentation of the experimental apparatus, the results for the ő≥-ray spectrum at ‚ąös = 7TeV are presented in this paper

    Sinteza i bioloŇ°ko vrednovanje novih derivata 2-fenil-benzimidazol-1-acetamida kao potencijalnih anthelmintika

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    The present study describes synthesis of a series of 2-phenyl benzimidazole-1-acetamide derivatives and their evaluation for anthelmintic activity using Indian adult earthworms, Pheretima posthuma. The structure of the title compounds was elucidated by elemental analysis and spectral data. The compounds 4-({[2-(4-nitrophenyl)-1H-benzimidazol-1-yl]acetyl}amino) benzoic acid (3a), N-ethyl-2-[2-(4-nitrophenyl)-1H-benzimidazol-1-yl] acetamide (3c), N-benzyl-2-[2-(4-nitrophenyl)-1H-benzimidazol-1-yl] acetamide (3d), N-(4-hydroxyphenyl)-2-[2-(4-nitrophenyl)-1H-benzimidazol-1-yl] acetamide (3f), 2-[2-(4-nitrophenyl)-1H-benzimidazol-1-yl]-N-phenylacetamide (3h), 2-[2-(4-chlorophenyl)-1H-benzimidazol-1-yl]-N\u27-phenylacetohydrazide (3k), 2-[2-(4-chlorophenyl)-1H-benzimidazol-1-yl]-N-(4-nitrophenyl) acetamide (3n) and 2-[2-(4-chlorophenyl)-1H-benzimidazol-1-yl]-N-phenylacetamide (3q) were better to paralyze worms whereas N-ethyl-2-[2-(4-nitrophenyl)-1H-benzimidazol-1-yl] acetamide (3c), N-(4-nitrophenyl)-2-[2-(4-nitrophenyl)-1H-benzimidazol-1yl] acetamide (3e), 4-({[2-(4-chlorophenyl)-1H-benzimidazol-1-yl] acetyl} amino) benzoic acid (3j), 2-[2-(4-chlorophenyl)-1H-benzimidazol-1-yl]-N-ethylacetamide (3l) and 2-[2-(4-chlorophenyl)-1H-benzimidazol-1-yl]-N-phenylacetamide (3q) were better to cause death of worms compared to the anthelmintic drug albendazole.U radu je opisana sinteza derivata 2-fenil-benzimidazol-1-acetamida i ispitivanje njihovog anthelmintińćkog djelovanja na odrasle indijske gliste, Pheretima posthuma. Struktura sintetiziranih spojeva odreńĎena je elementarnom analizom i spektroskopskim metodama. Spojevi 4-({[2-(4-nitrofenil)-1H-benzimidazol-1-il]acetil}amino) benzojeva kiselina (3a), N-etil-2-[2-(4-nitrofenil)-1H-benzimidazol-1-il] acetamid (3c), N-benzil-2-[2-(4-nitrofenil)-1H-benzimidazol-1-il] acetamid (3d), N-(4-hidroksifenil)-2-[2-(4-nitrofenil)-1H-benzimidazol-1-il] acetamid (3f), 2-[2-(4-nitrofenil)-1H-benzimidazol-1-il]-N-fenilacetamid (3h), 2-[2-(4-klorfenil)-1H-benzimidazol-1-il]-N\u27-fenilacetohidrazid (3k), 2-[2-(4-klorfenil)-1H-benzimidazol-1-il]-N-(4-nitrofenil) acetamid (3n) i 2-[2-(4-klorfenil)-1H-benzimidazol-1-il]-N-fenilacetamid (3q) jańće paraliziraju gliste, a N-etil-2-[2-(4-nitrofenil)-1H-benzimidazol-1-il] acetamid (3c), 2-[2-(4-nitrofenil)-1H-benzimidazol-1-il]-N-fenilacetamid (3h), 4-({[2-(4-klorfenil)-1H-benzimidazol-1-il]acetil}amino) benzojeva kiselina (3j), 2-[2-(4-klorfenil)-1H-benzimidazol-1-il]-N-etilacetamid (3l) i 2-[2-(4-klorfenil)-1H-benzimidazol-1-il]-N-fenilacetamid (3q) uńćinkovitije usmrńáuju gliste nego anthelmintik albendazol

    Nasopharyngeal pneumococcal carriage in South Asian infants:Results of observational cohort studies in vaccinated and unvaccinated populations

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    BACKGROUND: Nasopharyngeal pneumococcal carriage (NPC) is a prerequisite for invasive pneumococcal disease and reduced carriage of vaccine serotypes is a marker for the protection offered by the pneumococcal conjugate vaccine (PCV). The present study reports NPC during the first year of life in a vaccinated (with PCV10) cohort in Bangladesh and an unvaccinated cohort in India. METHODS: A total of 450 and 459 infants were recruited from India and Bangladesh respectively within 0-7 days after birth. Nasopharyngeal swabs were collected at baseline, 18 and 36 weeks after birth. The swabs were processed for pneumococcal culture and identification of serotypes by the Quellung test and polymerase chain reaction (PCR). An identical protocol was applied at both sites. RESULTS: Prevalence of NPC was 48% in the Indian and 54.8% in the Bangladeshi cohort at 18 weeks. It increased to 53% and 64.8% respectively at 36 weeks. The average prevalence of vaccine serotypes was higher in the Indian cohort (17.8% vs 9.8% for PCV-10 and 26.1% vs17.6% for PCV-13) with 6A, 6B, 19F, 23F, and 19A as the common serotypes. On the other hand, the prevalence of non-vaccine serotypes was higher (43.6% vs 27.1% for non-PCV13) in the Bangladeshi cohort with 34, 15B, 17F, and 35B as the common serotypes. Overcrowding was associated with increased risk of pneumococcal carriage. The present PCV-13 vaccine would cover 28%-30% and 47%-48% serotypes in the Bangladeshi and Indian cohorts respectively. CONCLUSIONS: South Asian infants get colonised with pneumococci early in infancy; predominantly vaccine serotypes in PCV na√Įve population (India) and non-vaccine serotypes in the vaccinated population (Bangladesh). These local findings are important to inform the public health policy and the development of higher valent pneumococcal vaccines

    Results from the LHCf experiment

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    LHCf is an experiment designed to study the very forward emission of neutral particles produced in collisions at the LHC. Its results can be used to calibrate the hadron interaction models of the Monte Carlo codes which allow the interpretation of energy spectrum and composition of high-energy cosmic rays as measured by air shower ground detectors. The experiment has already completed taking data in proton-proton collisions at ‚ąös = 900 GeV and at ‚ąös = 7TeV during 2009 and 2010. The detectors are now being upgraded and they will be installed again in the LHC tunnel for proton-ion collisions and for operation with protons at ‚ąös = 14TeV. In this paper results and comparisons with the predictions obtained from Monte Carlo simulations will be reported

    Comparison of hadron interaction models with measurement of forward spectra by the LHCf apparatus

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    The LHCf experiment is a forward experiment of LHC. The two LHCf detectors, each composed of a pair of sampling and imaging calorimeters, have been installed at the forward region of IP1 to measure energy and transverse momentum spectra of neutral particles emitted in the very forward region of LHC collisions (ő∑ > 8.4). The operation at 900 GeV and 7TeV pp collisions has been completed in the middle of July 2010. We present some preliminary results in this paper

    Forward photon energy spectrum at LHC 7 TeV p-p collisions measured by LHCf

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    Abstract The LHCf experiment is one of the LHC forward experiments. The aim is to measure the energy and the transverse momentum spectra of photons, neutrons and ŌÄ 0 's at the very forward region (the pseudo-rapidity range of ő∑ > 8.4 ), which should be critical data to calibrate hadron interaction models used in the air shower simulations. LHCf successfully operated at s = 900 GeV and s = 7 TeV proton‚Äďproton collisions in 2009 and 2010. We present the first physics result, single photon energy spectra at s = 7 TeV proton‚Äďproton collisions and the pseudo-rapidity ranges of ő∑ > 10.94 and 8.81 ő∑ 8.9 . The obtained spectra were compared with the predictions by several hadron interaction models and the models do not reproduce the experimental results perfectly
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