Flight envelopes of an aircraft in Mars atmosphere

Doktorska disertacija „Anvelope leta letelice u atmosferi Marsa" prikazuje detaljnu analizu aerodinamike i performansi, a na osnovu novog konceptualnog dizajna, lake letelice za atmosferu Marsa, ALPEMA. Takva letelica, omogućava atmosfersko ubacivanje (primena koncepta aeroshell), ali i direktno poletanje sa površine Marsa. Složena atmosfera Marsa zahteva pojednostavljenu, a opet efikasnu geometriju, koja može maksimizirati finesu. Marsov atmosferski pritisak, gustina, temperatura i varijacije brzine zvuka zahtevaju pomno izabrani motor, koji letelici ALPEMA donosi značajne prednosti u vezi sa iskorišćenjem snage. Efikasna vitkost i polara otpora dovode do optimalnih anvelopa leta, kao dokaza pune održivosti ALPEMA projekta. Posebne performanse i osnovna aerodinamika postavljaju granice i ograničenja projekta, u skladu s sličnim uporedivim pristupima. Izabrani propeler, tema kojoj je u disertaciji posvećena posebna pažnja, omogućuje ALPEMA da koristi maksimalnu snagu svog motora, prikazanu kroz Vmin i Vmax, koji su značajni ulazni podaci za anvelope leta. Anvelopa leta, kao ishodište celokupne analize, ima efikasnu širinu i profil za različite moguće misije. Specifični propeler i motor ALPEMA su jasna komparativna prednost u odnosu na slične, uporedive projekte, kao i u radu prikazana anvelopa leta.Doctoral dissertation „Flight Envelopes of an Aircraft in Mars Atmosphere" presents detailed aerodynamics and performances analysis, based on a new conceptual design of the light aircraft for Mars atmosphere, ALPEMA. Such aircraft allows atmospheric dropping (aeroshell concept application), as well as direct take-off from Martian surface. Complex Martian atmosphere demands for simplified yet efficient wing geometry, capable of maximizing Lift-to-Drag ratio. Martian atmospheric pressure, density, temperature and speed of sound variations, demand a scrutinized powerplant choice, which gives significant advantages to ALPEMA in the area of power exploitation. Efficient aspect ratio and drag polar lead to optimal flight envelopes as a proof of sustainability of ALPEMA project. Special performances and basic aerodynamics provide boundaries and constraints of the project, in line with similar and comparable approaches. Chosen propeller, topic which had significant attention in this dissertation, allows for ALPEMA to use maximum power capabilities of its engine, described through Vmin and Vmax, which are significant inputs for flight envelope. Flight envelope, as the goal of this entire analysis, provides effective width and profile for a variety of possible missions. ALPEMA’s specific propeller and engine are a certain decisive advantage when observed along comparable projects, together with its flight envelope

Conceptual Design and Flight Envelopes of a Light Aircraft for Mars Atmosphere

In this paper is presented a new conceptual design of the light aircraft for Mars atmosphere, ALPEMA. It allows atmospheric dropping (aeroshell), as well as direct take-off from Martian surface. Complex atmosphere demanded for simplified yet efficient wing geometry, capable of maximizing Lift-to-Drag ratio. Martian atmospheric pressure, density, temperature and speed of sound variations, demand a scrutinized powerplant choice. Efficient aspect ratio and drag polar lead to optimal flight envelopes as a proof of sustainability of ALPEMA project. Special performances and basic aerodynamics provide boundaries and constraints of the project, in line with similar approaches. Chosen propeller allows for ALPEMA to use maximum power capabilities of its engine, described through Vmin and Vmax, which are significant inputs for flight envelope. Envelope provides effective width and profile for a variety of possible missions. ALPEMA’s specific propeller and engine are a certain comparative advantage, together with its flight envelope

Search for neutral MSSM Higgs bosons decaying into a pair of bottom quarks

A search for neutral Higgs bosons decaying into a b (b) over bar quark pair and produced in association with at least one additional b quark is presented. This signature is sensitive to the Higgs sector of the minimal supersymmetric standard model (MSSM) with large values of the parameter tan beta. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 fb(-1). The results are combined with a previous analysis based on 7 TeV data. No signal is observed. Stringent upper limits on the cross section times branching fraction are derived for Higgs bosons with masses up to 900 GeV, and the results are interpreted within different MSSM benchmark scenarios, m(h)(max), m(h)(mod+), m(h)(mod-), light-stau and light-stop. Observed 95% confidence level upper limits on tan beta, ranging from 14 to 50, are obtained in the m(h)(mod+) benchmark scenario

Search for a standard model-like Higgs boson in the mu(+)mu(-) and e(+)e(-) decay channels at the LHC

A search is presented for a standard model-like Higgs boson decaying to the mu(+)mu(-) or e(+)e(-) final states based on proton-proton collisions recorded by the CMS experiment at the CERN LHC. The data correspond to integrated luminosities of 5.0 fb(-1) at a centre-of-mass energy of 7 TeV and 19.7 fb(-1) at 8 TeV for the mu(+)mu(-) search, and of 19.7 fb(-1) at 8 TeV for the e(+)e(-) search. Upper limits on the production cross section times branching fraction at the 95% confidence level are reported for Higgs boson masses in the range from 120 to 150 GeV. For a Higgs boson with a mass of 125 GeV decaying to mu(+)mu(-), the observed (expected) upper limit on the production rate is found to be 7.4 (6.5(-1.9)(+2.8)) times the standard model value. This corresponds to an upper limit on the branching fraction of 0.0016. Similarly, for e(+)e(-), an upper limit of 0.0019 is placed on the branching fraction, which is approximate to 3.7 x 10(5) times the standard model value. These results, together with recent evidence of the 125 GeV boson coupling to tau-leptons with a larger branching fraction consistent with the standard model, confirm that the leptonic couplings of the new boson are not flavour-universal. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V

Measurement of the t(t)over-bar production cross section in the dilepton channel in pp collisions at root s=8 TeV

The top-antitop quark (t (t) over bar) production cross section is measured in proton-proton collisions at root s = 8 TeV with the CMS experiment at the LHC, using a data sample corresponding to an integrated luminosity of 5.3 fb(-1). The measurement is performed by analysing events with a pair of electrons or muons, or one electron and one muon, and at least two jets, one of which is identified as originating from hadronisation of a bottom quark. The measured cross section is 239 +/- 2 (stat.) +/- 11 (syst.) +/- 6 (lum.) pb, for an assumed top-quark mass of 172.5 GeV, in agreement with the prediction of the standard model

Search for third-generation scalar leptoquarks in the t tau channel in proton-proton collisions at root s=8 TeV

A search for pair production of third-generation scalar leptoquarks decaying to top quark and tau lepton pairs is presented using proton-proton collision data at a center-of-mass energy of root s=8TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb(-1). The search is performed using events that contain an electron or a muon, a hadronically decaying tau lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a tau lepton, the existence of pair produced, charge -1/3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a tau lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling lambda(333)

Studies of dijet transverse momentum balance and pseudorapidity distributions in pPb collisions at root s(NN)=5.02 TeV

Dijet production has been measured in collisions at a nucleon-nucleon centre-of-mass energy of 5.02. A data sample corresponding to an integrated luminosity of 35 was collected using the Compact Muon Solenoid detector at the Large Hadron Collider. The dijet transverse momentum balance, azimuthal angle correlations, and pseudorapidity distributions are studied as a function of the transverse energy in the forward calorimeters (). For collisions, the dijet transverse momentum ratio and the width of the distribution of dijet azimuthal angle difference are comparable to the same quantities obtained from a simulated reference and insensitive to . In contrast, the mean value of the dijet pseudorapidity is found to change monotonically with increasing , indicating a correlation between the energy emitted at large pseudorapidity and the longitudinal motion of the dijet frame. The pseudorapidity distribution of the dijet system in minimum bias collisions is compared with next-to-leading-order perturbative QCD predictions obtained from both nucleon and nuclear parton distribution functions, and the data more closely match the latter

Measurements of the ZZ production cross sections in the 2l2 nu channel in proton-proton collisions at root s=7 and 8 TeV and combined constraints on triple gauge couplings

Measurements of the ZZ production cross sections in proton-proton collisions at center-of-mass energies of 7 and 8 TeV are presented. Candidate events for the leptonic decay mode ZZ - GT 2l2 nu. where l denotes an electron or a muon, are reconstructed and selected from data corresponding to an integrated luminosity of 5.1 (19.6) fb(-1) at 7 (8) TeV collected with the CMS experiment. The measured cross sections, sigma(pp - GT ZZ) = 5.1(1.4)(+1.5) (stat)(-1.1)(+1.4) (syst) +/- 0.1 (lumi) pb at 7 TeV, and 7.2(-0.8)(+0.8) (stat)(1.5)(+1.9) (syst) +/- 0.2 (lumi) pb at 8 TeV, are in good agreement with the standard model predictions with next-to-leading-order accuracy. The selected data are analyzed to search for anomalous triple gauge couplings involving the ZZ final state. In the absence of any deviation from the standard model predictions, limits are set on the relevant parameters. These limits are then combined with the previously published CMS results for ZZ in 4l final states, yielding the most stringent constraints on the anomalous couplings