Recent experiments have demonstrated sub decoherence time control of individual single-electron orbital qubits. Here we propose a quantum dot based scheme for generation and detection of pairs of orbitally entangled electrons on a timescale much shorter than the decoherence time. The electrons are entangled, via two-particle interference, and transferred to the detectors during a single cotunneling event, making the scheme insensitive to charge noise. For sufficiently long detector dot lifetimes, cross-correlation detection of the dot charges can be performed with real-time counting techniques, opening up for an unambiguous short-time Bell inequality test of orbital entanglement.PACS numbers: 73.63. Kv, 03.65.Ud, 03.67.Bg, 73.50.Td The concept of quantum entanglement has ever since its inception attracted much attention. Initially questioned because of its nonlocal properties, violating local realism [1, 2], entanglement has over the past decades emerged as an indispensable resource for quantum information processing [3]. Spurred by proposals for electronic spin-based quantum computing [4,5], spin qubit experiments [6,7] and demonstrations of long spin decoherence times [8], large efforts have been devoted to investigations of spin entanglement in nanostructures. Recent experimental progress comprises entanglement of singleelectron [9] and two-electron [10] spin qubits and splitting [11][12][13][14] of spin-singlet Cooper pairs in hybrid superconducting systems.In contrast to spin, entanglement between electronic orbital degrees of freedom [15,16], such as charge states in quantum dots [17] or edge channels in quantum Hall systems [18][19][20], has received limited attention. In particular, orbital entanglement has not been demonstrated experimentally. The key reason is arguably that superpositions of orbital states are sensitive to charge noise, resulting in short decoherence times, of the order of nanoseconds [21][22][23][24]. This has led to the widespread view that, despite all-electrical quantum state control and read-out, electronic orbital degrees of freedom cannot be harnessed for quantum information processing. Very recently this view was contested by demonstrations of fast, coherent operations of single-electron orbital qubits on the picosecond timescale [25][26][27], several orders of magnitude shorter than the decoherence time. These experiments motivate renewed efforts on orbital-based quantum information processing and call for novel schemes to generate and detect orbital entanglement on timescales well below the decoherence time.Here we propose such an entanglement scheme, based on coherent electron cotunneling [28] in a quantum dot system, see Fig. 1. During the cotunneling event, of the order of picoseconds [29,30], the electrons are entangled via two-particle interference [18,31] and simultaneously transferred to the detectors, fully preserving coherence [32,33]. We show, based on the full transfer statistics [34,35], that the entanglement can conveniently be detected by violating a Bell ine...