The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapidity-dependent difference (<math><mi>Δ</mi><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>) between <math><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup></math> (<math><mover><mrow><mi>u</mi></mrow><mo>‾</mo></mover><mi>c</mi></math>) and <math><msup><mrow><mover><mrow><mi>D</mi></mrow><mo>‾</mo></mover></mrow><mrow><mn>0</mn></mrow></msup></math> (<math><mi>u</mi><mover><mrow><mi>c</mi></mrow><mo>‾</mo></mover></math>) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of <math><mi>Δ</mi><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>. The rapidity-averaged value is found to be <math><mo>〈</mo><mi>Δ</mi><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>〉</mo><mo>=</mo><mn>0.001</mn><mo>±</mo><mn>0.001</mn><mspace width="0.25em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>0.003</mn><mspace width="0.25em"></mspace><mtext>(syst)</mtext></math> in PbPb collisions at <math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><msub><mrow></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msub></mrow></msqrt><mo>=</mo><mn>5.02</mn><mspace width="0.25em"></mspace><mtext>TeV</mtext></math>. In addition, the influence of the collision geometry is explored by measuring the <math><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup></math> and <math><msup><mrow><mover><mrow><mi>D</mi></mrow><mo>‾</mo></mover></mrow><mrow><mn>0</mn></mrow></msup></math>mesons <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> and triangular flow coefficient (<math><msub><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msub></math>) as functions of rapidity, transverse momentum (<math><msub><mrow><mi>p</mi></mrow><mrow><mi>T</mi></mrow></msub></math>), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt <math><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup></math> meson <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> values is observed, while the <math><msub><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msub></math> is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry.

Armenia

A.M. Sirunyan

A. Tumasyan

Austria

W. Adam

F. Ambrogi

T. Bergauer

M. Dragicevic

J. Erö

A. Escalante Del Valle

R. Frühwirth

M. Jeitler

N. Krammer

L. Lechner

D. Liko

T. Madlener

I. Mikulec

N. Rad

J. Schieck

R. Schöfbeck

M. Spanring

S. Templ

W. Waltenberger

C.E. Wulz

M. Zarucki

Belarus

V. Chekhovsky

A. Litomin

V. Makarenko

J. Suarez Gonzalez

Belgium

M.R. Darwish

E.A. De Wolf

D. Di Croce

X. Janssen

T. Kello

A. Lelek

M. Pieters

H. Rejeb Sfar

H. Van Haevermaet

P. Van Mechelen

S. Van Putte

N. Van Remortel

F. Blekman

E.S. Bols

S.S. Chhibra

J. D'Hondt

J. De Clercq

D. Lontkovskyi

S. Lowette

I. Marchesini

S. Moortgat

Q. Python

S. Tavernier

W. Van Doninck

P. Van Mulders

D. Beghin

B. Bilin

B. Clerbaux

G. De Lentdecker

H. Delannoy

B. Dorney

L. Favart

A. Grebenyuk

A.K. Kalsi

I. Makarenko

L. Moureaux

L. Pétré

A. Popov

N. Postiau

E. Starling

L. Thomas

C. Vander Velde

P. Vanlaer

D. Vannerom

L. Wezenbeek

T. Cornelis

D. Dobur

I. Khvastunov

M. Niedziela

C. Roskas

K. Skovpen

M. Tytgat

W. Verbeke

B. Vermassen

M. Vit

G. Bruno

F.J.J. Bury

C. Caputo

P. David

C. Delaere

M. Delcourt

I.S. Donertas

A. Giammanco

V. Lemaitre

J. Prisciandaro

A. Saggio

A. Taliercio

M. Teklishyn

P. Vischia

S. Wuyckens

J. Zobec

Brazil

G.A. Alves

G. Correia Silva

Measurement of prompt D And meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at

The CP -violating weak phase <math><msub><mrow><mi>ϕ</mi></mrow><mrow><mi>s</mi></mrow></msub></math> and the decay width difference <math><mi>Δ</mi><msub><mrow><mi>Γ</mi></mrow><mrow><mi>s</mi></mrow></msub></math> between the light and heavy <math><msubsup><mrow><mi>B</mi></mrow><mrow><mi>s</mi></mrow><mrow><mn>0</mn></mrow></msubsup></math> mass eigenstates are measured with the CMS detector at the LHC in a sample of <math><mn>48</mn><mspace width="0.2em"></mspace><mn>500</mn></math>reconstructed <math><msubsup><mrow><mi>B</mi></mrow><mrow><mi>s</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo>→</mo><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><mspace width="0.2em"></mspace><mi>ϕ</mi><mo>(</mo><mn>1020</mn><mo>)</mo><mo>→</mo><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup><mspace width="0.2em"></mspace><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup></math> events. The measurement is based on a data sample corresponding to an integrated luminosity of <math><mn>96.4</mn><mrow><mspace width="0.2em"></mspace><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>, collected in proton-proton collisions at <math><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mspace width="0.2em"></mspace><mtext>TeV</mtext></math> in 2017–2018. To extract the values of <math><msub><mrow><mi>ϕ</mi></mrow><mrow><mi>s</mi></mrow></msub></math> and <math><mi>Δ</mi><msub><mrow><mi>Γ</mi></mrow><mrow><mi>s</mi></mrow></msub></math>, a time-dependent and flavor-tagged angular analysis of the <math><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup></math> final state is performed. The analysis employs a dedicated tagging trigger and a novel opposite-side muon flavor tagger based on machine learning techniques. The measurement yields <math><msub><mrow><mi>ϕ</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>11</mn><mo>±</mo><mn>50</mn><mspace width="0.2em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>10</mn><mspace width="0.2em"></mspace><mtext>(syst)</mtext><mrow><mspace width="0.20em"></mspace><mtext>mrad</mtext></mrow></math> and <math><mi>Δ</mi><msub><mrow><mi>Γ</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mn>0.114</mn><mo>±</mo><mn>0.014</mn><mspace width="0.2em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>0.007</mn><mspace width="0.2em"></mspace><mtext>(syst)</mtext><msup><mrow><mspace width="0.20em"></mspace><mtext>ps</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, in agreement with the standard model predictions. When combined with the previous CMS measurement at <math><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>8</mn><mspace width="0.2em"></mspace><mtext>TeV</mtext></math>, the following values are obtained: <math><msub><mrow><mi>ϕ</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>21</mn><mo>±</mo><mn>44</mn><mspace width="0.2em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>10</mn><mspace width="0.2em"></mspace><mtext>(syst)</mtext><mrow><mspace width="0.20em"></mspace><mtext>mrad</mtext></mrow></math>, <math><mi>Δ</mi><msub><mrow><mi>Γ</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mn>0.1032</mn><mo>±</mo><mn>0.0095</mn><mspace width="0.2em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>0.0048</mn><mspace width="0.2em"></mspace><mtext>(syst)</mtext><msup><mrow><mspace width="0.20em"></mspace><mtext>ps</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, a significant improvement over the 8 TeV result.

F.M. Pitters

A. Morton

M. Gruchala

F. Bury

K. Mondal

Measurement of the -violating Phase In the Channel in Proton-proton Collisions at

The first measurement of the inclusive cross section for top quark pairs (<math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover></math>) produced in association with two additional charm jets is presented. The analysis uses the dileptonic final states of <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover></math> events produced in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of <math><mn>41.5</mn><mspace width="0.25em"></mspace><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, recorded by the CMS experiment at the LHC. A new charm jet identification algorithm provides input to a neural network that is trained to distinguish among <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover></math> events with two additional charm (<math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mi>c</mi><mover><mrow><mi>c</mi></mrow><mo>‾</mo></mover></math>), bottom (<math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mi>b</mi><mover><mrow><mi>b</mi></mrow><mo>‾</mo></mover></math>), and light-flavour or gluon (<math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mtext>LL</mtext></math>) jets. By means of a template fitting procedure, the inclusive <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mi>c</mi><mover><mrow><mi>c</mi></mrow><mo>‾</mo></mover></math>, <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mi>b</mi><mover><mrow><mi>b</mi></mrow><mo>‾</mo></mover></math>, and <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mtext>LL</mtext></math> cross sections are simultaneously measured, together with their ratios to the inclusive <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover></math> + two jets cross section. This provides measurements of the <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mi>c</mi><mover><mrow><mi>c</mi></mrow><mo>‾</mo></mover></math> and <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mo>‾</mo></mover><mi>b</mi><mover><mrow><mi>b</mi></mrow><mo>‾</mo></mover></math> cross sections of <math><mn>10.1</mn><mo>±</mo><mn>1.2</mn><mspace width="0.25em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>1.4</mn><mspace width="0.25em"></mspace><mtext>(syst)</mtext><mspace width="0.2em"></mspace><mtext>pb</mtext></math> and <math><mn>4.54</mn><mo>±</mo><mn>0.35</mn><mspace width="0.25em"></mspace><mtext>(stat)</mtext><mo>±</mo><mn>0.56</mn><mspace width="0.25em"></mspace><mtext>(syst)</mtext><mspace width="0.2em"></mspace><mtext>pb</mtext></math>, respectively, in the full phase space. The results are compared and found to be consistent with predictions from two different matrix element generators with next-to-leading order accuracy in quantum chromodynamics, interfaced with a parton shower simulation.

D. Müller

A.R. Sahasransu

K. Lee

G. Mestdach

A. Bethani

S. Wertz

C. Hensel

A. Moraes

W.L. Aldá Júnior

First measurement of the cross section for top quark pair production with additional charm jets using dileptonic final states in pp collisions at

A search is performed for <math><msup><mrow><mi>W</mi></mrow><mrow><mo>′</mo></mrow></msup></math> bosons decaying to a top and a bottom quark in the all-hadronic final state, in proton-proton collisions at a center-of-mass energy of 13TeV. The analyzed data were collected by the CMS experiment between 2016 and 2018 and correspond to an integrated luminosity of 137<math><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. Deep neural network algorithms are used to identify the jet initiated by the bottom quark and the jet containing the decay products of the top quark when the W boson from the top quark decays hadronically. No excess above the estimated standard model background is observed. Upper limits on the production cross sections of <math><msup><mrow><mi>W</mi></mrow><mrow><mo>′</mo></mrow></msup></math> bosons decaying to a top and a bottom quark are set. Both left- and right-handed <math><msup><mrow><mi>W</mi></mrow><mrow><mo>′</mo></mrow></msup></math> bosons with masses below 3.4TeV are excluded at 95% confidence level, and the most stringent limits to date on <math><msup><mrow><mi>W</mi></mrow><mrow><mo>′</mo></mrow></msup></math> bosons decaying to a top and a bottom quark in the all-hadronic final state are obtained.

J.W. Andrejkovic

S. Chatterjee

M. Mahdavikhorrami

M. Vanden Bemden

M. Barroso Ferreira Filho

H. Brandao Malbouisson

Search for W′ bosons decaying to a top and a bottom quark at In the Hadronic Final State

A search for leptoquarks produced singly and in pairs in proton-proton collisions is presented. We consider the leptoquark (LQ) to be a scalar particle of charge −1/3e coupling to a top quark plus a tau lepton (<math><mi>t</mi><mi>τ</mi></math>) or a bottom quark plus a neutrino (<math><mi>b</mi><mi>ν</mi></math>), or a vector particle of charge +2/3e, coupling to <math><mi>t</mi><mi>ν</mi></math> or <math><mi>b</mi><mi>τ</mi></math>. These choices are motivated by models that can explain a series of anomalies observed in the measurement of B meson decays. In this analysis the signatures <math><mi>t</mi><mi>τ</mi><mi>ν</mi><mi>b</mi></math> and <math><mi>t</mi><mi>τ</mi><mi>ν</mi></math> are probed, using data recorded by the CMS experiment at the CERN LHC at <math><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mtext> TeV</mtext></math> and that correspond to an integrated luminosity of 137 fb$^{−1}$. These signatures have not been previously explored in a dedicated search. The data are found to be in agreement with the standard model prediction. Lower limits at 95% confidence level are set on the LQ mass in the range 0.98–1.73 TeV, depending on the LQ spin and its coupling λ to a lepton and a quark, and assuming equal couplings for the two LQ decay modes considered. These are the most stringent constraints to date on the existence of leptoquarks in this scenario.

Search for singly and pair-produced leptoquarks coupling to third-generation fermions in proton-proton collisions at

A search is performed for the rare decay <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>γ</mi></math> in proton-proton collisions at <math><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mspace width="0.2em"></mspace><mtext>TeV</mtext></math>. Data corresponding to an integrated luminosity of <math><mn>137</mn><mrow><mspace width="0.2em"></mspace><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> were collected during 2016 to 2018 with the CMS detector. This analysis exploits a novel search strategy based on W boson production in top quark pair events. An inclusive search for the <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>γ</mi></math> decay is not optimal at the LHC because of the high trigger thresholds. Instead, a trigger selection is exploited in which the W boson originating from one of the top quarks is used to tag the event in a leptonic decay. The W boson emerging from the other top quark is used to search for the <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>γ</mi></math> signature. Such decays are characterized by an isolated track pointing to a large energy deposit, and by an isolated photon of large transverse momentum. The presence of b quark jets reduces the background from the hadronization of light-flavor quarks and gluons. The <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>γ</mi></math> decay is not observed. An upper exclusion limit is set to this branching fraction, corresponding to <math><mn>1.50</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></math> at 95% confidence level, whereas the expected upper exclusion limit is <math><msubsup><mrow><mn>0.85</mn></mrow><mrow><mo>−</mo><mn>0.29</mn></mrow><mrow><mo>+</mo><mn>0.52</mn></mrow></msubsup><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>.

Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at

The second-order Fourier coefficients (<math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>) characterizing the azimuthal distributions of Image 3 and Image 4 mesons produced in PbPb collisions at <math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><msub><mrow></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msub></mrow></msqrt><mo>=</mo><mn>5.02</mn><mspace width="0.25em"></mspace><mtext>TeV</mtext></math> are studied. The Image 5 mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of <math><mn>1.7</mn><mspace width="0.25em"></mspace><msup><mrow><mtext>nb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The scalar product method is used to extract the <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> coefficients of the azimuthal distributions. Results are reported for the rapidity range <math><mo>|</mo><mi>y</mi><mo>|</mo><mo>&lt;</mo><mn>2.4</mn></math>, in the transverse momentum interval <math><mn>0</mn><mo>&lt;</mo><msub><mrow><mi>p</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>&lt;</mo><mn>50</mn><mspace width="0.25em"></mspace><mtext>GeV</mtext><mo>/</mo><mi>c</mi></math>, and in three centrality ranges of 10–30%, 30–50% and 50–90%. In contrast to the <math><mi>J</mi><mo>/</mo><mi>ψ</mi></math> mesons, the measured <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> values for the Image 5 mesons are found to be consistent with zero.

M. Flechl

I. Krätschmer

V. Drugakov

V. Mossolov

E. Belchior Batista Das Chagas

W. Carvalho

J. Chinellato

E. Coelho

E.M. Da Costa

G.G. Da Silveira

D. De Jesus Damiao

Measurement of the azimuthal anisotropy of And mesons in PbPb collisions at

Measurements of the second Fourier harmonic coefficient (<math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>) of the azimuthal distributions of prompt and nonprompt D$^{0}$ mesons produced in <math><mi>p</mi><mi>p</mi></math> and <math><mi>p</mi><mtext>Pb</mtext></math> collisions are presented. Nonprompt D$^{0}$ mesons come from beauty hadron decays. The data samples are collected by the CMS experiment at nucleon-nucleon center-of-mass energies of 13 and 8.16 TeV, respectively. In high multiplicity <math><mi>p</mi><mi>p</mi></math> collisions, <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> signals for prompt charm hadrons are reported for the first time, and are found to be comparable to those for light-flavor hadron species over a transverse momentum (<math><msub><mrow><mi>p</mi></mrow><mrow><mi>T</mi></mrow></msub></math>) range of 2–6 GeV. Compared at similar event multiplicities, the prompt D$^{0}$ meson <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> values in <math><mi>p</mi><mi>p</mi></math> and <math><mi>p</mi><mtext>Pb</mtext></math> collisions are similar in magnitude. The <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> values for open beauty hadrons are extracted for the first time via nonprompt D$^{0}$ mesons in <math><mi>p</mi><mtext>Pb</mtext></math> collisions. For <math><msub><mrow><mi>p</mi></mrow><mrow><mi>T</mi></mrow></msub></math> in the range of 2–5 GeV, the results suggest that <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> for nonprompt D$^{0}$ mesons is smaller than that for prompt D$^{0}$ mesons. These new measurements indicate a positive charm hadron <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> in <math><mi>p</mi><mi>p</mi></math> collisions and suggest a mass dependence in <math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> between charm and beauty hadrons in the <math><mi>p</mi><mtext>Pb</mtext></math> system. These results provide insights into the origin of heavy-flavor quark collectivity in small systems.

Studies of charm and beauty hadron long-range correlations in pp and pPb collisions at LHC energies

Event-by-event long-range correlations of azimuthal anisotropy Fourier coefficients <math><mo>(</mo><msub><mi>v</mi><mi>n</mi></msub><mo>)</mo></math> in 8.16 TeV <math><mrow><mi>p</mi><mi>Pb</mi></mrow></math> data, collected by the CMS experiment at the CERN Large Hadron Collider, are extracted using a subevent four-particle cumulant technique applied to very low multiplicity events. Each combination of four charged particles is selected from either two, three, or four distinct subevent regions of a pseudorapidity range from <math><mrow><mo>−</mo><mn>2.4</mn></mrow></math> to 2.4 of the CMS tracker, and with transverse momentum between 0.3 and 3.0 GeV. Using the subevent cumulant technique, correlations between <math><msub><mi>v</mi><mi>n</mi></msub></math> of different orders are measured as functions of particle multiplicity and compared to the standard cumulant method without subevents over a wide event multiplicity range. At high multiplicities, the <math><msub><mi>v</mi><mn>2</mn></msub></math> and <math><msub><mi>v</mi><mn>3</mn></msub></math> coefficients exhibit an anticorrelation; this behavior is observed consistently using various methods. The <math><msub><mi>v</mi><mn>2</mn></msub></math> and <math><msub><mi>v</mi><mn>4</mn></msub></math> correlation strength is found to depend on the number of subevents used in the calculation. As the event multiplicity decreases, the results from different subevent methods diverge because of different contributions of noncollective or few-particle correlations. Correlations extracted with the four-subevent method exhibit a tendency to diminish monotonically toward the lowest multiplicity region (about 20 charged tracks) investigated. These findings extend previous studies to a significantly lower event multiplicity range and establish the evidence for the onset of long-range collective multiparticle correlations in small system collisions.

E. Asilar

J. Brandstetter

V.M. Ghete

J. Hrubec

H. Rohringer

D. Spitzbart

A. Taurok

J. Wittmann

J. Lauwers

S. Abu Zeid

I. De Bruyn

K. Deroover

G. Flouris

L. Moreels

I. Van Parijs

H. Brun

G. Fasanella

R. Goldouzian

T. Lenzi

J. Luetic

Q. Wang

A. Fagot

M. Gul

D. Poyraz

D. Trocino

N. Zaganidis

H. Bakhshiansohi

O. Bondu

S. Brochet

Correlations of azimuthal anisotropy Fourier harmonics with subevent cumulants in <math><mrow><mi>p</mi><mi>Pb</mi></mrow></math> collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>8.16</mn><mspace width="0.16em"></mspace><mi>TeV</mi></mrow></math>

The first measurements of production cross sections of polarized same-sign <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup></math> boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of <math><mn>13</mn><mspace width="0.25em"></mspace><mtext>TeV</mtext></math>, corresponding to an integrated luminosity of <math><mn>137</mn><mrow><mspace width="0.25em"></mspace><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup></math> scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88) fbis set on the production cross section for longitudinally polarized same-sign <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup></math> boson pairs. The electroweak production of same-sign <math><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup></math> boson pairs with at least one of the W bosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.

Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at TeV