Equimultiple locus of embedded algebroid surfaces and blowing-up in characteristic zero

The smooth equimultiple locus of embedded algebroid surfaces appears naturally in many resolution process, both classical and modern.In this paper we explore how it changes by blowing–up.Junta de AndalucíaMinisterio de Ciencia y Tecnologí

Hironaka's characteristic polygon and effective resolution of surfaces

Hironaka’s concept of characteristic polyhedron of a singularity has been one of the most powerful and fruitful ideas of the last decades in singularity theory. In fact, since then combinatorics have become a major tool in many important results. However, this seminal concept is still not enough to cope with some effective problems: for instance, giving a bound on the maximum number of blowing–ups to be performed on a surface before its multiplicity decreases. This short note shows why such a bounding is not possible, at least with the original definitions.Universidad de SevillaMinisterio de Ciencia y TecnologíaJunta de Andalucí

Equimultiple locus of embedded algebroid surfaces and blowing-up in arbitrary characteristic

This paper extends previous results of the authors, concerning the behaviour of the equimultiple locus of algebroid surfaces under blowing–up, to arbitrary characteristic.Ministerio de Educación y CienciaJunta de Andalucí

Pilar Pisón Casares, in memoriam

Estamos habituados a describir objetos matemáticos, a elaborar teorías, conjeturar resultados, demostrar asertos o refutar hipótesis, pero no a escribir de una persona, más aún si con ella tenemos vínculos afectivos que no sabemos expresar adecuadamente. Es necesario precisar que, para ofrecer una semblanza de nuestra querida compañera Pilar Pisón, tenemos que entrelazar las dos pasiones que han recorrido su vida: su familia y las matemáticas. Pretendemos presentar la enorme figura de esta mujer que hemos conocido, y por tanto querido, por su humildad en el trabajo personal y, sobre todo, colectivo, incapaz de aparecer en el primer plano, sino sosteniendo al que lo ocupara. La fotografía de la familia de Pilar, su marido e hijas, así lo expresa. La enfermedad y la muerte han pretendido destruirla pero no lo han conseguido. Con la fortaleza con que Pilar se ha enfrentado a ellas hemos aprendido facetas profundamente valiosas de esta mujer que, cuanto más débil se hacía, más sabiduría transmitía. Ha sostenido un gran combate en el que, con el apoyo de su fe, ha vencido la Vida

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Search for third-generation scalar leptoquarks in the tt channel in proton-proton collisions at √s=8 TeV

A search for pair production of third-generation scalar leptoquarks decaying to top quark and t lepton pairs is presented using proton-proton collision data at a center-of-mass energy of vs=8 TeV 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 t 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 t 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 t lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling λ′333

Measurement of multijet azimuthal correlations and determination of the strong coupling in proton-proton collisions at s=13 TeV\sqrt{s}=13\,\text {Te}\hspace{-.08em}\text {V}

A measurement is presented of a ratio observable that provides a measure of the azimuthal correlations among jets with large transverse momentum pT . This observable is measured in multijet events over the range of pT=360–3170 GeV based on data collected by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 134 fb$^{−1}$ . The results are compared with predictions from Monte Carlo parton-shower event generator simulations, as well as with fixed-order perturbative quantum chromodynamics (pQCD) predictions at next-to-leading-order (NLO) accuracy obtained with different parton distribution functions (PDFs) and corrected for nonperturbative and electroweak effects. Data and theory agree within uncertainties. From the comparison of the measured observable with the pQCD prediction obtained with the NNPDF3.1 NLO PDFs, the strong coupling at the Z boson mass scale is α$_S$(m$_Z$) = 0.1177 ± 0.0013 (exp)$\frac {+0.0116}{−0.0073}$ (theo) = 0.1177$\frac {+0.0117}{−0.0074}$ , where the total uncertainty is dominated by the scale dependence of the fixed-order predictions. A test of the running of α$_S$ in the TeV region shows no deviation from the expected NLO pQCD behaviour

Measurement of multijet azimuthal correlations and determination of the strong coupling in proton-proton collisions at s=13 TeV\sqrt{s}=13\,\text {Te}\hspace{-.08em}\text {V}

A measurement is presented of a ratio observable that provides a measure of the azimuthal correlations among jets with large transverse momentum pT . This observable is measured in multijet events over the range of pT=360–3170 GeV based on data collected by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 134 fb$^{−1}$ . The results are compared with predictions from Monte Carlo parton-shower event generator simulations, as well as with fixed-order perturbative quantum chromodynamics (pQCD) predictions at next-to-leading-order (NLO) accuracy obtained with different parton distribution functions (PDFs) and corrected for nonperturbative and electroweak effects. Data and theory agree within uncertainties. From the comparison of the measured observable with the pQCD prediction obtained with the NNPDF3.1 NLO PDFs, the strong coupling at the Z boson mass scale is α$_S$(m$_Z$) = 0.1177 ± 0.0013 (exp)$\frac {+0.0116}{−0.0073}$ (theo) = 0.1177$\frac {+0.0117}{−0.0074}$ , where the total uncertainty is dominated by the scale dependence of the fixed-order predictions. A test of the running of α$_S$ in the TeV region shows no deviation from the expected NLO pQCD behaviour

A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer

A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp → pp + Z/γ + X, in proton-tagged events from proton–proton collisions at √s = 13 TeV, recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600–1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. odelindependent upper limits on the visible production cross section of pp → pp + Z/γ + X are set

Proton reconstruction with the CMS-TOTEM Precision Proton Spectrometer

The Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb-1 in proton-proton (pp) collisions at the LHC at 13 TeV (Run 2). This paper describes the key features of the PPS alignment and optics calibrations, the proton reconstruction procedure, as well as the detector efficiency and the performance of the PPS simulation. The reconstruction and simulation are validated using a sample of (semi)exclusive dilepton events. The performance of PPS has proven the feasibility of continuously operating a near-beam proton spectrometer at a high luminosity hadron collider