First information on the timelike electromagnetic structure of baryons in the second resonance region has been obtained from measurements of the dielectron (e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math>) invariant mass and angular distributions with the High Acceptance Di-Electron Spectrometer (HADES) at GSI, using a secondary pion beam impinging on CH <inf>2</inf> and C targets. The quasi-free reaction <math altimg='si1.svg'><msup><mi>&#960;</mi><mo>&#8722;</mo></msup></math>+ p &#8239;&#8594;&#8239; n e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math> at <math altimg='si12.svg'><msqrt><msub><mi>s</mi><mrow><mi>&#960;</mi><mi mathvariant='normal'>p</mi></mrow></msub></msqrt></math> = 1.49&#8239;GeV is isolated in several analysis steps. The data set provides a crucial test for the description of baryon timelike transitions. Close to the kinematical limit the meassured e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math> mass distribution shows deviations by up to a factor 8 from the Dalitz decay of a point-like baryon. Various theoretical approaches connecting information from hadronic and electromagnetic channels in the spacelike and timelike regime compare well with the measured e <math altimg='si2.svg'><msup><mrow /><mo>+</mo></msup></math>e <math altimg='si3.svg'><msup><mrow /><mo>&#8722;</mo></msup></math> invariant mass distribution, including (i) a Vector Meson Dominance amplitude containing direct photon and vector meson ( <italic>&#961;</italic>) couplings to the baryon, (ii) electromagnetic timelike baryon transition form factors in a covariant spectator-quark model, where meson cloud effects dominate, and (iii) application of dispersion theory, which demonstrates the importance of the pion electromagnetic form factors.

Germany

France

R. Abou Yassine

J. Adamczewski-Musch

O. Arnold

E.T. Atomssa

M. Becker

C. Behnke

J.C. Berger-Chen

Portugal

A. Blanco

C. Blume

M. Böhmer

Czechia

L. Chlad

Poland

I. Ciepał

S. Deb

C. Deveaux

D. Dittert

J. Dreyer

E. Epple

L. Fabbietti

J. Förtsch

P. Fonte

C. Franco

J. Friese

I. Fröhlich

T. Galatyuk

Spain

J.A. Garzón

R. Gernhäuser

R. Greifenhagen

M. Grunwald

M. Gumberidze

S. Harabasz

T. Heinz

T. Hennino

C. Höhne

F. Hojeij

R. Holzmann

M. Idzik

B. Kämpfer

K-H Kampert

B. Kardan

V. Kedych

S. Kim

I. Koenig

W. Koenig

M. Kohls

J. Kolas

B.W. Kolb

G. Korcyl

G. Kornakov

R. Kotte

W. Krueger

A. Kugler

T. Kunz

R. Lalik

K. Lapidus

S. Linev

F. Linz

L. Lopes

M. Lorenz

T. Mahmoud

L. Maier

A. Malige

J. Markert

S. Maurus

V. Metag

J. Michel

D.M. Mihaylov

A. Molenda

C. Müntz

R. Münzer

M. Nabroth

L. Naumann

K. Nowakowski

A. Opíchal

J. Orliński

J.-H Otto

Cyprus

Y. Parpottas

M. Parschau

C. Pauly

V. Pechenov

O. Pechenova

K. Piasecki

J. Pietraszko

T. Povar

K. Prościński

A. Prozorov

W. Przygoda

K. Pysz

B. Ramstein

N. Rathod

P. Rodriguez-Ramos

A. Rost

A. Rustamov

P. Salabura

K. Scharmann

T. Scheib

N. Schild

K. Schmidt-Sommerfeld

H. Schuldes

E. Schwab

F. Scozzi

First measurement of massive virtual photon emission from N* baryon resonances

The jet cross section and jet-substructure observables in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mo>+</mo><mi>p</mi></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>200</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> were measured by the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC). Jets are reconstructed from charged-particle tracks and electromagnetic-calorimeter clusters using the anti-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math> algorithm with a jet radius of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi><mo>=</mo><mn>0.3</mn></math> for jets with transverse momentum within <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>8.0</mn><mo>&lt;</mo><msub><mi>p</mi><mi>T</mi></msub><mo>&lt;</mo><mn>40.0</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></math> and pseudorapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>η</mi><mo stretchy="false">|</mo><mo>&lt;</mo><mn>0.15</mn></math>. Measurements include the jet cross section, as well as distributions of SoftDrop-groomed momentum fraction (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>z</mi><mi>g</mi></msub></math>), charged-particle transverse momentum with respect to jet axis (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>j</mi><mi>T</mi></msub></math>), and radial distributions of charged particles within jets (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>r</mi></math>). Also measured was the distribution of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ξ</mi><mo>=</mo><mo>−</mo><mi>ln</mi><mo stretchy="false">(</mo><mi>z</mi><mo stretchy="false">)</mo></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>z</mi></math> is the fraction of the jet momentum carried by the charged particle. The measurements are compared to theoretical next-to and next-to-next-to-leading-order calculations, the pythia and herwig event generators, and to other existing experimental results. Indicated from these measurements is a lower particle multiplicity in jets at RHIC energies when compared to models. Also noted are implications for future jet measurements with sPHENIX at RHIC as well as at the future Electron-Ion Collider.

Hungary

N.J. Abdulameer

United States

U. Acharya

C. Aidala

N.N. Ajitanand

Japan

Y. Akiba

R. Akimoto

J. Alexander

M. Alfred

V. Andrieux

Russia

S. Antsupov

K. Aoki

N. Apadula

H. Asano

T.C. Awes

B. Azmoun

V. Babintsev

M. Bai

China

X. Bai

N.S. Bandara

B. Bannier

E. Bannikov

K.N. Barish

S. Bathe

V. Baublis

C. Baumann

S. Baumgart

A. Bazilevsky

M. Beaumier

R. Belmont

A. Berdnikov

Y. Berdnikov

L. Bichon

D. Black

B. Blankenship

D.S. Blau

J.S. Bok

V. Borisov

K. Boyle

M.L. Brooks

J. Bryslawskyj

H. Buesching

V. Bumazhnov

S. Butsyk

S. Campbell

R. Cervantes

C.H. Chen

D. Chen

M. Chiu

C.Y. Chi

I.J. Choi

South Korea

J.B. Choi

S. Choi

Sweden

P. Christiansen

T. Chujo

V. Cianciolo

Israel

Z. Citron

B.A. Cole

M. Connors

R. Corliss

N. Cronin

N. Crossette

M. Csanád

T. Csörgő

L. D’Orazio

T.W. Danley

A. Datta

M.S. Daugherity

G. David

K. DeBlasio

K. Dehmelt

A. Denisov

A. Deshpande

E.J. Desmond

L. Ding

A. Dion

D. Dixit

V. Doomra

J.H. Do

O. Drapier

A. Drees

K.A. Drees

J.M. Durham

A. Durum

Measurement of inclusive jet cross section and substructure in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mo>+</mo><mi>p</mi></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>200</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>