D. Galli - Academia.edu (original) (raw)

Papers by D. Galli

Physical Review Letters, 2006

Nuclear Physics A, 2001

ABSTRACT

Physics Letters B, 1996

The frequency of the protonium annihilation channel p-p + KSKL has been measured at three differe... more The frequency of the protonium annihilation channel p-p + KSKL has been measured at three different target densities: liquid hydrogen (LH) , gaseous hydrogen at NTP conditions and gaseous hydrogen at low pressure (5 mbar). The obtained results are: f(pp-+ KsKL, LH) = (7.8 f 0.7sut * 0.

Nuclear Physics B - Proceedings Supplements, 1997

Results on np annihilation frequencies into pi+pi0, pi+eta and K+ Ks final states in the n moment... more Results on np annihilation frequencies into pi+pi0, pi+eta and K+ Ks final states in the n momentum range between 50 and 400 MeV/c are presented. Information about np annihilation dynamics at low energy have been extracted as well as the first determination of the D-wave contribution to the annihilation in flight below 400 MeV/c. This result is compared with an independent analysis of the np annihilation cross section data.

Nuclear Physics B - Proceedings Supplements, 1997

The results of the spin-parity analysis of the annihilation reaction pp -&amp;amp;amp;amp... more The results of the spin-parity analysis of the annihilation reaction pp -&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; pi+pi-pi0 at rest are presented. For the first time data from liquid, NTP and low pressure hydrogen are fitted simultaneously. This tecnique allows to disentangle unambiguously the contributions of the different initial atomic states. The results concern the weights of the partial waves, masses and widths of the 0++, 1- and 2++ resonances produced in the annihilation.

Nuclear Physics A, 1993

... a Dip. di Scienze Fisiche, Universita&amp;amp;#x27; di Cagliari and INFN, Sez. di Cag... more ... a Dip. di Scienze Fisiche, Universita&amp;amp;#x27; di Cagliari and INFN, Sez. di Cagliari, Cagliari, Italy. b Politecnico di Torino and INFN, Sez. di Torino, Torino, Italy. c Ist. di Fisica, Universita&amp;amp;#x27; di Torino and INFN, Sez. di Torino, Torino, Italy. d Dip. ...

Il Nuovo Cimento A, 1997

In this document the pretrigger system developed for the electromagnetic calorimeter of the HERA-... more In this document the pretrigger system developed for the electromagnetic calorimeter of the HERA-B experiment is described. The system owns a lot of frontier features for calorimetry-based triggers and its design performances are such that some possible implementations of it can be foreseen for the future high-energy collider experiments.

Il Nuovo Cimento A Series 11, 1994

... 7), L. SANTI(13) MG SAPOZHNIKOV(1), N. SEMPRINI CESARI(8), S. SERCI(2), n. SPIGHI(8) P. TEMNI... more ... 7), L. SANTI(13) MG SAPOZHNIKOV(1), N. SEMPRINI CESARI(8), S. SERCI(2), n. SPIGHI(8) P. TEMNIKOV(2), S. TESSARO(11), F ... the value Xpull = 0 and must have standard deviation %uH = 1. The procedure starts with ~in values obtained by Monte Carlo simulation, to ...

EPJ direct, 2002

A direct physical interpretation of the K-matrix and P-vector approach is proposed; the aspects r... more A direct physical interpretation of the K-matrix and P-vector approach is proposed; the aspects relevant to the understanding of the formalism are commented in detail. The procedures developed are extended to include the general case of non-resonant terms in ...

$Research paper thumbnail of Observation of Two New Ξ_{b}^{-} Baryon Resonances$

Physical review letters, Jan 13, 2015

Two structures are observed close to the kinematic threshold in the Ξ_{b}^{0}π^{-} mass spectrum ... more Two structures are observed close to the kinematic threshold in the Ξ_{b}^{0}π^{-} mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb^{-1}, recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bds are expected in this mass region: the spin-parity J^{P}=(1/2)^{+} and J^{P}=(3/2)^{+} states, denoted Ξ_{b}^{'-} and Ξ_{b}^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be…

JHEP, 2014

The first observation of the Cabibbo-suppressed decay Λ 0 b → J/ψpπ − is reported using a data sa... more The first observation of the Cabibbo-suppressed decay Λ 0 b → J/ψpπ − is reported using a data sample of proton-proton collisions at 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb −1. A prominent signal is observed and the branching fraction relative to the decay mode Λ 0 b → J/ψpK − is determined to be B(Λ 0 b → J/ψpπ −) B(Λ 0 b → J/ψpK −) = 0.0824 ± 0.0025 (stat) ± 0.0042 (syst). A search for direct CP violation is performed. The difference in the CP asymmetries between these two decays is found to be A CP (Λ 0 b → J/ψpπ −) − A CP (Λ 0 b → J/ψpK −) = (+5.7 ± 2.4 (stat) ± 1.2 (syst))%, which is compatible with CP symmetry at the 2.2σ level.

$Research paper thumbnail of Search for CP violation in <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mi>D</mi><mo lspace="0em" rspace="0em">±</mo></msup><mo>→</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo lspace="0em" rspace="0em">±</mo></msup></mrow><annotation encoding="application/x-tex">D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm}</annotation></semantics></math>D±→KS0K± and <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msubsup><mi>D</mi><mi>s</mi><mo lspace="0em" rspace="0em">±</mo></msubsup><mo>→</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mo lspace="0em" rspace="0em">±</mo></msup></mrow><annotation encoding="application/x-tex">D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm}</annotation></semantics></math>Ds±→KS0π± decays$

Journal of High Energy Physics, 2014

We study large N 2+1 dimensional fermions in the fundamental representation of an SU(N) k Chern S... more We study large N 2+1 dimensional fermions in the fundamental representation of an SU(N) k Chern Simons gauge group in the presence of a uniform background magnetic field for the U(1) global symmetry of this theory. The magnetic field modifies the Schwinger Dyson equation for the propagator in an interesting way; the product between the self energy and the Greens function is replaced by a Moyal star product. Employing a basis of functions previously used in the study of non-commutative solitons, we are able to exactly solve the Schwinger Dyson equation and so determine the fermion propagator. The propagator has a series of poles (and no other singularities) whose locations yield a spectrum of single particle energies at arbitrary t' Hooft coupling and chemical potential. The usual free fermion Landau levels spectrum is shifted and broadened out; we compute the shifts and widths of these levels at arbitrary t'Hooft coupling. As a check on our results we independently solve for the propagators of the conjecturally dual theory of Chern Simons gauged large N fundamental Wilson Fisher bosons also in a background magnetic field but this time only at zero chemical potential. The spectrum of single particle states of the bosonic theory precisely agrees with those of the fermionic theory under Bose-Fermi duality.

Journal of High Energy Physics, 2014

Production of Υ mesons in proton-lead collisions at a nucleon-nucleon centreof-mass energy √ s NN... more Production of Υ mesons in proton-lead collisions at a nucleon-nucleon centreof-mass energy √ s NN = 5 TeV is studied with the LHCb detector. The analysis is based on a data sample corresponding to an integrated luminosity of 1.6 nb −1. The Υ mesons of transverse momenta up to 15 GeV/c are reconstructed in the dimuon decay mode. The rapidity coverage in the centre-of-mass system is 1.5 < y < 4.0 (forward region) and −5.0 < y < −2.5 (backward region). The forward-backward production ratio and the nuclear modification factor for Υ(1S) mesons are determined. The data are compatible with the predictions for a suppression of Υ(1S) production with respect to proton-proton collisions in the forward region, and an enhancement in the backward region. The suppression is found to be smaller than in the case of prompt J/ψ mesons.

Physical Review D, 2013

The time-dependent CP asymmetry in B 0 s ! J=c K þ K À decays is measured using pp collision data... more The time-dependent CP asymmetry in B 0 s ! J=c K þ K À decays is measured using pp collision data at ffiffi ffi s p ¼ 7 TeV, corresponding to an integrated luminosity of 1:0 fb À1 , collected with the LHCb detector. The decay-time distribution is characterized by the decay widths À L and À H of the light and heavy mass eigenstates of the B 0 s-" B 0 s system and by a CP-violating phase s. In a sample of 27 617 B 0 s ! J=c K þ K À decays, where the dominant contribution comes from B 0 s ! J=c decays, these parameters are measured to be s ¼ 0:07 AE 0:09ðstatÞ AE 0:01ðsystÞ rad, À s ðÀ L þ À H Þ=2 ¼ 0:663 AE 0:005ðstatÞ AE 0:006ðsystÞ ps À1 , and ÁÀ s À L À À H ¼ 0:100 AE 0:016ðstatÞ AE 0:003ðsystÞ ps À1 , corresponding to the single most precise determination of s , ÁÀ s , and À s. The result of performing a combined analysis with B 0 s ! J=c þ À decays gives s ¼ 0:01 AE 0:07ðstatÞ AE 0:01ðsystÞ rad, À s ¼ 0:661 AE 0:004ðstatÞ AE 0:006ðsystÞ ps À1 , and ÁÀ s ¼ 0:106 AE 0:011ðstatÞ AE 0:007ðsystÞ ps À1. All measurements are in agreement with the Standard Model predictions.

Physics Letters B, 2014

The LHCb measurement of the lifetime ratio of the Λ 0 b baryon to the B 0 meson is updated using ... more The LHCb measurement of the lifetime ratio of the Λ 0 b baryon to the B 0 meson is updated using data corresponding to an integrated luminosity of 3.0 fb −1 collected using 7 and 8 TeV centre-of-mass energy pp collisions at the LHC. The decay modes used are Λ 0 b → J/ψ pK − and B 0 → J/ψ π + K − , where the π + K − mass is consistent with that of the K * 0 (892) meson. The lifetime ratio is determined with unprecedented precision to be 0.974 ± 0.006 ± 0.004, where the first uncertainty is statistical and the second systematic. This result is in agreement with original theoretical predictions based on the heavy quark expansion. Using the current world average of the B 0 lifetime, the Λ 0 b lifetime is found to be 1.479 ± 0.009 ± 0.010 ps.

Physics Letters B, 2014

The CP-violating asymmetry View the MathML sourceasls is studied using semileptonic decays of Vie... more The CP-violating asymmetry View the MathML sourceasls is studied using semileptonic decays of View the MathML sourceBs0 and View the MathML sourceB¯s0 mesons produced in pp collisions at a centre-of-mass energy of 7 TeV at the LHC, exploiting a data sample corresponding to an integrated luminosity of 1.0 fb−11.0 fb−1. The reconstructed final states are View the MathML sourceDs±, with the View the MathML sourceDs± particle decaying in the ±± mode. The View the MathML sourceDs± yields are summed over View the MathML sourceB¯s0 and View the MathML sourceBs0 initial states, and integrated with respect to decay time. Data-driven methods are used to measure efficiency ratios. We obtain View the MathML sourceasls=(−0.06±0.50±0.36)%, where the first uncertainty is statistical and the second systematic.

Physical review letters, Jan 31, 2013

The quantum numbers of the X(3872) meson are determined to be J(PC)=1(++) based on angular correl... more The quantum numbers of the X(3872) meson are determined to be J(PC)=1(++) based on angular correlations in B(+)→X(3872)K(+) decays, where X(3872)→π(+)π(-)J/ψ and J/ψ→μ(+)μ(-). The data correspond to 1.0 fb(-1) of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements J(PC)=2(-+) is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state.

$Research paper thumbnail of Addendum: Observation of double charm production involving open charm in pp collisions at $ \sqrt{s} $ = 7 TeV$

Journal of High Energy Physics, 2014

Addendum: Observation of double charm production involving open charm in pp collisions at p root ... more Addendum: Observation of double charm production involving open charm in pp collisions at p root s=7 TeV.

Physics Letters B, 2003

The π + π − π 0 , K + K − π 0 and K ± K 0 π ∓ final states produced bypp annihilation at rest at ... more The π + π − π 0 , K + K − π 0 and K ± K 0 π ∓ final states produced bypp annihilation at rest at three different hydrogen target densities have been analyzed in the frame of a coupled channel analysis together with ππ and πK scattering data. Here we present the main results which concern masses, widths, ππ and K K partial widths of all the involved resonances (J P = 0 + , 1 − , 2 +), the direct determination of Γ K K /Γ ππ ratio for f 0 (1370) and f 0 (1500) (Γ K K /Γ ππ = 0.91 ± 0.20 and Γ K K /Γ ππ = 0.25 ± 0.03, respectively), the determination of a 0 (1300) parameters (M = 1303 ± 16 MeV; Γ = 92 ± 16 MeV) and the observation of two different high mass ρ signals associated to ρ(1450) and ρ(1700) (M = 1182 ± 30 MeV;

Physical Review Letters, 2006

Nuclear Physics A, 2001

ABSTRACT

Physics Letters B, 1996

Nuclear Physics B - Proceedings Supplements, 1997

Nuclear Physics A, 1993

Il Nuovo Cimento A, 1997

Il Nuovo Cimento A Series 11, 1994

EPJ direct, 2002

$Research paper thumbnail of Observation of Two New Ξ_{b}^{-} Baryon Resonances$

Physical review letters, Jan 13, 2015

JHEP, 2014

Journal of High Energy Physics, 2014

Physical Review D, 2013

Physics Letters B, 2014

Physical review letters, Jan 31, 2013

$Research paper thumbnail of Addendum: Observation of double charm production involving open charm in pp collisions at $ \sqrt{s} $ = 7 TeV$

Journal of High Energy Physics, 2014

Physics Letters B, 2003